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提交 1660e300 编写于 作者: T Thomas G. Lockhart
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doc/src/sgml/ref/commands.sgml
浏览文件 @ 1660e300
<Chapter Id="commands">
<Title>Commands</Title>
<chapter Id="sql-commands">
<title>Commands</title>
<Para>
</Para>
<para>
</para>
&alterTable;
&alterUser;
......@@ -22,10 +22,33 @@
&createTable;
&createTrigger;
&createType;
&createUser;
&createView;
&declare;
&delete;
&dropFunction;
&reset;
&revoke;
&rollback;
&select;
&set;
&show;
&update;
</Chapter>
</chapter>
<chapter Id="sql-functions">
<title>SQL Functions</title>
<para>
</para>
&currentDate;
&currentTime;
&currentTimestamp;
&currentUser;
</chapter>
<!-- Keep this comment at the end of the file
Local variables:
......
doc/src/sgml/ref/create_user.sgml 0 → 100644
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<REFENTRY ID="SQL-CREATEUSER-1">
<REFMETA>
<REFENTRYTITLE>
CREATE USER
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
CREATE USER
</REFNAME>
<REFPURPOSE>
Creates account information for a new user
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
CREATE USER<REPLACEABLE CLASS="PARAMETER"> username</REPLACEABLE>
[WITH PASSWORD <REPLACEABLE CLASS="PARAMETER">password</REPLACEABLE>]
[CREATEDB | NOCREATEDB]
[CREATEUSER | NOCREATEUSER]
[IN GROUP <REPLACEABLE CLASS="PARAMETER">groupname</REPLACEABLE> [, ...] ]
[VALID UNTIL '<REPLACEABLE CLASS="PARAMETER">abstime</REPLACEABLE>']
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-CREATEUSER-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">username</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The name of the user.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">password</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The WITH PASSWORD clause sets the user's password within
the "<filename>pg_shadow</filename>" table. For this reason,
<filename>"pg_shadow</filename>" is no
longer accessible to the instance of PostgreSQL that the
PostgreSQL user's password is initially set to NULL.
<comment>The text here has got garbled.</comment>
When a
user's password in the "<filename>pg_shadow</filename>"
table is NULL, user
authentication proceeds as it historically has (HBA,
PG_PASSWORD, etc). However, if a password is set for a
user, a new authentication system supplants any other
configured for the PostgreSQL instance, and the password
stored in the "<filename>pg_shadow</filename>" table is used
for authentication.
For more details on how this authentication system
functions see pg_crypt(3). If the WITH PASSWORD clause is
omitted, the user's password is set to the empty
string with equates to a NULL value in the authentication
system mentioned above.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue> CREATEDB/NOCREATEDB</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
These clauses define a user's ability to create databases.
If CREATEDB is specified, the user being defined will
be allowed to create his own databases. Using NOCREATEDB
will deny a user the ability to create databases. If this
clause is omitted, NOCREATEDB is used by default.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue>CREATEUSER/NOCREATEUSER</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
These clauses determine whether a user will be permitted to
create new
users in an instance of PostgreSQL.
Omitting this clause will set the user's value of this
attribute to be NOCREATEUSER.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">groupname</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
A name of a group into which to insert the user as a new member.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">abstime</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The VALID UNTIL clause sets an absolute time after which the
user's PostgreSQL login is no longer valid. Please note that
if a user does not have a password defined in the
"<filename>pg_shadow</filename>"
table, the valid until date will not be checked
during user authentication. If this clause is omitted,
a NULL value is stored in "<filename>pg_shadow</filename>"
for this attribute,
and the login will be valid for all time.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-CREATEUSER-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>CREATE USER</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
Message returned if the command completes successfully.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue>ERROR: removeUser: user "<replaceable class="parameter">username</replaceable>" does not exist</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
if "<replaceable class="parameter">username</replaceable>" not found.
</PARA>
<comment>I don't understand this and I don't know how to get
this error message.</comment>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-CREATEUSER-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
CREATE USER will add a new user to an instance of PostgreSQL.
</PARA>
<PARA>
The new user will be given a <filename>usesysid</filename> of:
'<command>SELECT MAX(usesysid) + 1 FROM pg_shadow</command>'.
This means that
PostgreSQL users' <filename>usesysid</filename>s will not
correspond to their operating
system(OS) user ids. The exception to this rule is
the '<literal>postgres</literal>' user, whose OS user id
is used as the
<filename>usesysid</filename> during the initdb process.
If you still want the
OS user id and the <filename>usesysid</filename> to match
for any given user,
use the "createuser" script provided with the PostgreSQL
distribution.
</PARA>
<REFSECT2 ID="R2-SQL-CREATEUSER-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
CREATE USER statement is a PostgreSQL language extension.
</PARA>
<para>
Use DROP USER or ALTER USER statements to remove or modify a user
account.</para>
<para>
Refer to the <filename>pg_shadow</filename> table for further information.
</para>
<programlisting>
Table = pg_shadow
+--------------------------+--------------------------+-------+
| Field | Type | Length|
+--------------------------+--------------------------+-------+
| usename | name | 32 |
| usesysid | int4 | 4 |
| usecreatedb | bool | 1 |
| usetrace | bool | 1 |
| usesuper | bool | 1 |
| usecatupd | bool | 1 |
| passwd | text | var |
| valuntil | abstime | 4 |
+--------------------------+--------------------------+-------+
</programlisting>
</REFSECT2>
<REFSECT1 ID="R1-SQL-CREATEUSER-2">
<TITLE>
Usage
</TITLE>
<PARA>
Create a user with no password:
</PARA>
<ProgramListing>
CREATE USER jonathan
</ProgramListing>
<PARA>
Create a user with a password:
</PARA>
<ProgramListing>
CREATE USER davide WITH PASSWORD jw8s0F4
</ProgramListing>
<para>
Create a user with a password, whose account is valid until the end of 2001.
Note that after one second has ticked in 2002, the account is not
valid:
</para>
<ProgramListing>
CREATE USER miriam WITH PASSWORD jw8s0F4 VALID UNTIL 'Jan 1 2002'
</ProgramListing>
<para>
Create an account where the user can create databases:
</para>
<ProgramListing>
CREATE USER manuel WITH PASSWORD jw8s0F4 CREATEDB
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-CREATEUSER-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-CREATEUSER-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
There is no CREATE USER statement in SQL92.
</PARA>
</REFENTRY>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
sgml-parent-document:nil
sgml-default-dtd-file:"../reference.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:"/usr/lib/sgml/catalog"
sgml-local-ecat-files:nil
End:
-->
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doc/src/sgml/ref/create_view.sgml 0 → 100644
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<REFENTRY ID="SQL-CREATEVIEW-1">
<REFMETA>
<REFENTRYTITLE>
CREATE VIEW
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
CREATE VIEW
</REFNAME>
<REFPURPOSE>
Constructs a virtual table
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
CREATE VIEW <REPLACEABLE CLASS="PARAMETER">view</REPLACEABLE>
AS SELECT <REPLACEABLE CLASS="PARAMETER">query</REPLACEABLE>
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-CREATEVIEW-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">view</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The name of a view to be created.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">query</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
An SQL query which will provide the columns and rows of the view.
</PARA>
<PARA>
Refer to the SELECT statement for more information
about valid arguments.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-CREATEVIEW-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>CREATE</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The message returned if the view is successfully created.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue>
WARN amcreate: "<replaceable class="parameter">view</replaceable>" relation already exists
</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
This error occurs if the view specified already exists in the database.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue>NOTICE create: attribute named "<replaceable class="parameter">column</replaceable>" has an unknown type</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The view will be created having a column with an unknown type
if you do not specify it. For example, the following command gives
an error:
<programlisting>
CREATE VIEW vista AS SELECT 'Hello World'
</programlisting>
whereas this command does not:
<programlisting>
CREATE VIEW vista AS SELECT 'Hello World'::text
</programlisting>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-CREATEVIEW-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
CREATE VIEW will define a view of a table. This view is
not physically materialized. Specifically, a query
rewrite retrieve rule is automatically generated
to support retrieve operations on views.
</PARA>
<REFSECT2 ID="R2-SQL-CREATEVIEW-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
Use the DROP VIEW statement to drop views.
</PARA>
</refsect2>
<REFSECT2 ID="R2-SQL-CREATEVIEW-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Bugs
</TITLE>
<para>
Currently, views are read only.
</para>
</REFSECT2>
<REFSECT1 ID="R1-SQL-CREATEVIEW-2">
<TITLE>
Usage
</TITLE>
<PARA>
Create a view consisting of all Comedy films:
</PARA>
<ProgramListing>
CREATE VIEW kinds AS
SELECT *
FROM films
WHERE kind = 'Comedy';
SELECT * FROM kinds;
code |title |did| date_prod|kind |len
-----+-------------------------+---+----------+----------+------
UA502|Bananas |105|1971-07-13|Comedy | 01:22
C_701|There's a Girl in my Soup|107|1970-06-11|Comedy | 01:36
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-CREATEVIEW-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-CREATEVIEW-5">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
SQL92 specifies some additional capabilities for the CREATE VIEW statement:
</PARA>
<programlisting>
CREATE VIEW <replaceable class="parameter">view</replaceable> [ <replaceable class="parameter">column</replaceable> [, ...] ]
AS SELECT <replaceable class="parameter">expression</replaceable> [AS <replaceable class="parameter">colname</replaceable>] [, ...]
FROM <replaceable class="parameter">table</replaceable>
[WHERE <replaceable class="parameter">condition</replaceable>]
[ WITH [ CASCADE | LOCAL ] CHECK OPTION ]
</programlisting>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>CHECK OPTION</ReturnValue>
</TERM>
<LISTITEM>
<PARA> This option is to do with updatable views.
All INSERTs and UPDATEs on the view will be
checked to ensure data satisfy the view-defining
condition. If they do not, the update will be rejected.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue>LOCAL</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
Check for integrity on this view.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue>CASCADE</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
Check for integrity on this view and on any dependent
view. CASCADE is assumed if neither CASCADE nor LOCAL is specified.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect2>
</refsect1>
</REFENTRY>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
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sgml-exposed-tags:nil
sgml-local-catalogs:"/usr/lib/sgml/catalog"
sgml-local-ecat-files:nil
End:
-->
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<REFENTRY ID="SQL-CURRENT-DATE-1">
<REFMETA>
<REFENTRYTITLE>
SQL_CURRENT_DATE
</REFENTRYTITLE>
<REFMISCINFO>SQL - Functions</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
SQL_CURRENT_DATE
</REFNAME>
<REFPURPOSE>
- returns the current date, (i.e "today").
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
CURRENT_DATE
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-CURRENT-DATE-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>None</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-CURRENT-DATE-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>Returns "<replaceable class="parameter">today</replaceable>"</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-CURRENT-DATE-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
The niladic CURRENT_DATE function has a data type of
DATE and returns the date at the time that it is run.
</PARA>
<REFSECT2 ID="R2-SQL-CURRENT-DATE-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
Refer to SET DATESTYLE for further information about date format.
</PARA>
</REFSECT2>
<REFSECT1 ID="R1-SQL-CURRENT-DATE-2">
<TITLE>
Usage
</TITLE>
<PARA>
Insert the date of insertion into a row:
</PARA>
<ProgramListing>
INSERT INTO films
VALUES ('TM999','Ben Hur',105,CURRENT_DATE,'Action',NULL);
</ProgramListing>
<PARA>
Display CURRENT-DATE:
</PARA>
<ProgramListing>
SELECT CURRENT_DATE AS today;
today
------------
1998-03-31
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-CURRENT-DATE-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-CURRENT-DATE-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
Full compatibility.
</PARA>
</refsect2>
</refsect1>
</REFENTRY>
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sgml-local-ecat-files:nil
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<REFENTRY ID="SQL-CURRENT-TIME-1">
<REFMETA>
<REFENTRYTITLE>
SQL_CURRENT_TIME
</REFENTRYTITLE>
<REFMISCINFO>SQL - Functions</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
SQL_CURRENT_TIME
</REFNAME>
<REFPURPOSE>
- returns the current local time, (i.e "now").
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
CURRENT_TIME
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-CURRENT-TIME-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>None</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-CURRENT-TIME-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>Returns "<replaceable class="parameter">now</replaceable>"</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-CURRENT-TIME-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
The niladic CURRENT_TIME function has a data type of
TIME and returns the local time when it is run.
</PARA>
<REFSECT2 ID="R2-SQL-CURRENT-TIME-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA> Refer to the SET TIME ZONE statement for a further description
of local time.
</PARA>
</REFSECT2>
<REFSECT1 ID="R1-SQL-CURRENT-TIME-2">
<TITLE>
Usage
</TITLE>
<PARA>Display CURRENT_TIME:
</PARA>
<ProgramListing>
SELECT CURRENT_TIME AS now;
now
-----------
17:41:31+02
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-CURRENT-TIME-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-CURRENT-TIME-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
SQL92 specifies some additional capabilities for CURRENT_TIME:
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>
CURRENT_TIME [ (<replaceable class="parameter">scale</replaceable>) ]</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The optional scale for CURRENT_TIME, if specified, is an
unsigned integer representing the number of digits in the
optional seconds fraction of the time value represented
by the function.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFENTRY>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
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sgml-exposed-tags:nil
sgml-local-catalogs:"/usr/lib/sgml/catalog"
sgml-local-ecat-files:nil
End:
-->
\ No newline at end of file
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<REFENTRY ID="SQL-CURRENT-TIMESTAMP-1">
<REFMETA>
<REFENTRYTITLE>
SQL_CURRENT_TIMESTAMP
</REFENTRYTITLE>
<REFMISCINFO>SQL - Functions</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
SQL_CURRENT_TIMESTAMP
</REFNAME>
<REFPURPOSE>
returns the current timestamp, (i.e the
date "today" concatenated with time "now").
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<synopsis>
CURRENT_TIMESTAMP
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-CURRENT-TIMESTAMP-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>None</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-CURRENT-TIMESTAMP-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>Returns "<replaceable class="parameter">today</replaceable>" and "<replaceable class="parameter">now</replaceable>".</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-CURRENT-TIMESTAMP-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
The niladic CURRENT_TIMESTAMP function has a data type of
TIMESTAMP and returns the date and local time at which it is run.
</PARA>
<REFSECT2 ID="R2-SQL-CURRENT-TIMESTAMP-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
Refer to the SET TIME ZONE statement for a further description
of local time.
</PARA>
</REFSECT2>
<REFSECT1 ID="R1-SQL-CURRENT-TIMESTAMP-2">
<TITLE>
Usage
</TITLE>
<PARA>
Display CURRENT_TIMESTAMP:
</PARA>
<ProgramListing>
SELECT CURRENT_TIMESTAMP AS date_and_time;
date_and_time
----------------------
1998-03-31 07:41:21-08
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-CURRENT-TIMESTAMP-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-CURRENT-TIMESTAMP-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
SQL92 specifies some additional capabilities for CURRENT_TIMESTAMP:
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>CURRENT_TIMESTAMP [ (<replaceable class="parameter">scale</replaceable>) ]</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The optional scale for CURRENT_TIMESTAMP, if specified, is an
unsigned integer representing the number of digits in the
optional seconds fraction of the time value represented
by the function.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</para>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</refsect2>
</refsect1>
</REFENTRY>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
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sgml-exposed-tags:nil
sgml-local-catalogs:"/usr/lib/sgml/catalog"
sgml-local-ecat-files:nil
End:
-->
\ No newline at end of file
doc/src/sgml/ref/current_user.sgml 0 → 100644
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<REFENTRY ID="SQL-CURRENT-USER-1">
<REFMETA>
<REFENTRYTITLE>
SQL_CURRENT_USER
</REFENTRYTITLE>
<REFMISCINFO>SQL - Functions</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
SQL_CURRENT_USER
</REFNAME>
<REFPURPOSE>
- returns the current user name.
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
CURRENT_USER
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-CURRENT-USER-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>None</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-CURRENT-USER-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>The name of the current user.</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-CURRENT-USER-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
The niladic CURRENT_USER function returns a string of type "name"
whose value represents a user name identification.
</PARA>
<REFSECT2 ID="R2-SQL-CURRENT-USER-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
Data type "name" is a non-standard 31-character type for storing
system identifiers.
</PARA>
</REFSECT2>
<REFSECT1 ID="R1-SQL-CURRENT-USER-2">
<TITLE>
Usage
</TITLE>
<PARA>
Display CURRENT_USER
</PARA>
<ProgramListing>
SELECT CURRENT_USER AS who_am_i;
who_am_i
------------
jose
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-CURRENT-USER-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-CURRENT-USER-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
SQL92 specifies some additional niladic USER functions:
</PARA>
<variablelist>
<varlistentry>
<term>CURRENT_USER / USER</term>
<listitem>
<para>
USER is a synonym for CURRENT_USER.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SESSION_USER</term>
<listitem>
<para>
The SESSION_USER function returns the SQL-session user name.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SYSTEM_USER</term>
<listitem>
<para>
The SYSTEM_USER function returns the database's initial default user.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
A niladic USER function returns a SQL_TEXT character string whose
value represents a user name.
</para>
</refsect2>
</refsect1>
</REFENTRY>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
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sgml-exposed-tags:nil
sgml-local-catalogs:"/usr/lib/sgml/catalog"
sgml-local-ecat-files:nil
End:
-->
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doc/src/sgml/ref/declare.sgml 0 → 100644
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<REFENTRY ID="SQL-DECLARESTATEMENT-1">
<REFMETA>
<REFENTRYTITLE>
DECLARE STATEMENT
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
DECLARE STATEMENT
</REFNAME>
<REFPURPOSE>
Declares a cursor
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
DECLARE <replaceable class="parameter">cursor</replaceable> [ BINARY ]
FOR SELECT <replaceable class="parameter">query</replaceable>
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-DECLARESTATEMENT-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>BINARY</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The BINARY keyword causes the cursor to fetch data in binary
rather than in ASCII format.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">cursor</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The cursor's name.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">query</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
An SQL query which will provide the rows to be governed by the
cursor.
</PARA>
<PARA>
Refer to the SELECT statement for further information about
valid arguments.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-DECLARESTATEMENT-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue>SELECT</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The message returned if the SELECT is run successfully.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue>NOTICE
BlankPortalAssignName: portal "<replaceable class="parameter">cursor</replaceable>" already exists</ReturnValue>
</TERM>
<LISTITEM>
<PARA>
This error occurs if cursor "<replaceable class="parameter">cursor</replaceable>" is already declared.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-DECLARESTATEMENT-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
DECLARE allows a user to create cursors, which can be used to retrieve
a small number of rows at a time out of a larger query. Cursors can return
data either in ASCII or in binary foramt.
</PARA>
<PARA>
Normal cursors return data in ASCII format. Since
data is stored natively in binary format, the system must
do a conversion to produce the ASCII format. In addition,
ASCII formats are often larger in size than binary format.
Once the information comes back in ASCII, the client
application often has to convert it to a binary format to
manipulate it anyway.
</PARA>
<PARA>
BINARY cursors give you back the data in the native binary
representation. So binary cursors will tend to be a
little faster since they suffer less conversion overhead.
For example, for an integer column, you get a C integer number like ^A
using a binary cursor, while you get a string value like '1'
using the non binary cursor.
</PARA>
<PARA>
However, ASCII is architecture-neutral whereas binary
representation can differ between different machine architectures.
Therefore, if your client machine and server machine use different
representations, you will probably not want your data returned in
binary format.
Again, if you intend to display the data in
ASCII, getting it back in ASCII will save you some
effort on the client side.
</PARA>
<REFSECT2 ID="R2-SQL-DECLARESTATEMENT-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
Cursors are only available in transactions.
</PARA>
<PARA>
PostgreSQL does not have an explicit <command>OPEN cursor</command>
statement; a cursor is considered to be open when it is DECLAREd.
</PARA>
</REFSECT2>
</refsect1>
<REFSECT1 ID="R1-SQL-DECLARESTATEMENT-2">
<TITLE>
Usage
</TITLE>
<PARA>
To declare a cursor:
</PARA>
<ProgramListing>
DECLARE liahona CURSOR
FOR SELECT * FROM films;
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-DECLARESTATEMENT-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-DECLARESTATEMENT-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
SQL92 specifies some additional capabilities for the DECLARE statement:
</PARA>
<synopsis>
DECLARE cursor [ INSENSITIVE ] [ SCROLL ] CURSOR
FOR SELECT expression
[ ORDER BY column [, ... ] [ ASC | DESC ]
[ FOR { READ ONLY | UPDATE [ OF column [, ...] ] } ]
</synopsis>
<variablelist>
<varlistentry>
<term></term>
<listitem>
<variablelist>
<varlistentry>
<term>INSENSITIVE</term>
<listitem>
<para>
UPDATE and DELETE CURRENT operations are not allowed
if the cursor is declared to be INSENSITIVE.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SCROLL</term>
<listitem>
<para>
If SCROLL is not specified, only FETCH NEXT will be allowed.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>FOR READ ONLY/UPDATE</term>
<listitem>
<para>
If READ ONLY is specified, UPDATE/DELETE CURRENT operations
will not be allowed.
</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
</variablelist>
</REFENTRY>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
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sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
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sgml-exposed-tags:nil
sgml-local-catalogs:"/usr/lib/sgml/catalog"
sgml-local-ecat-files:nil
End:
-->
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<REFENTRY ID="SQL-DELETE-1">
<REFMETA>
<REFENTRYTITLE>
DELETE
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
DELETE
</REFNAME>
<REFPURPOSE>
Deletes rows from a table
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
DELETE FROM <REPLACEABLE CLASS="PARAMETER">table</REPLACEABLE> [ WHERE <REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE> ]
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-DELETE-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">table</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
The name of an existing table.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<ReturnValue><replaceable class="parameter">condition</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
This is an SQL selection query which returns the rows which
are to be deleted.
</PARA>
<PARA>
Refer to the SELECT statement for further description
of the WHERE clause.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-DELETE-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<ReturnValue> DELETE <replaceable class="parameter">count</replaceable></ReturnValue>
</TERM>
<LISTITEM>
<PARA>
Message returned if items are successfully deleted. The
<replaceable class="parameter">count</replaceable> is the number
of rows deleted.
</PARA>
<PARA>
If <replaceable class="parameter">count</replaceable> is 0,
no rows are deleted.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-DELETE-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
DELETE removes rows which satisfy the WHERE <replaceable class="parameter">condition</replaceable>,
from the specified table.
</PARA>
<PARA>
If the <replaceable class="parameter">condition</replaceable> is absent,
the effect is to delete all rows in the table.
The result is a valid, but empty table.
</PARA>
<PARA>
You must have write access to the table in order to modify
it, as well as read access to any table whose values are
read in the <replaceable class="parameter">condition</replaceable>.
</PARA>
</REFSECT1>
<REFSECT1 ID="R1-SQL-DELETE-2">
<TITLE>
Usage
</TITLE>
<PARA>
Remove all films but musicals:
</PARA>
<ProgramListing>
DELETE FROM films WHERE kind &lt;&gt; 'Musical';
SELECT * FROM films;
code |title |did| date_prod|kind |len
-----+-------------------------+---+----------+----------+------
UA501|West Side Story |105|1961-01-03|Musical | 02:32
TC901|The King and I |109|1956-08-11|Musical | 02:13
WD101|Bed Knobs and Broomsticks|111| |Musical | 01:57
</ProgramListing>
<para>
Clear the table films:
</para>
<programlisting>
DELETE FROM films;
SELECT * FROM films;
code|title|did|date_prod|kind|len
----+-----+---+---------+----+---
(0 rows)
</programlisting>
</REFSECT1>
<REFSECT1 ID="R1-SQL-DELETE-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-DELETE-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
SQL92 defines a different syntax for a positioned DELETE statement:
</PARA>
<synopsis>
DELETE FROM <replaceable class="parameter">table</replaceable> WHERE CURRENT OF <replaceable class="parameter">cursor</replaceable>
</synopsis>
<para>
where <replaceable class="parameter">cursor</replaceable> identifies an open cursor.</para>
</refsect2>
</refsect1>
</REFENTRY>
<!-- Keep this comment at the end of the file
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mode: sgml
sgml-omittag:t
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sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
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sgml-exposed-tags:nil
sgml-local-catalogs:"/usr/lib/sgml/catalog"
sgml-local-ecat-files:nil
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-->
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<REFENTRY ID="SQL-RESET">
<REFMETA>
<REFENTRYTITLE>
RESET
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
RESET
</REFNAME>
<REFPURPOSE>
Restores run-time parameters for session to default values
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-09-01</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
RESET <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE>
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-RESET-1">
<REFSECT2INFO>
<DATE>1998-09-01</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
Refer to the SET statement for more information on available
variables.
</variablelist>
</REFSECT2>
<REFSECT2 ID="R2-SQL-RESET-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
RESET VARIABLE
</TERM>
<LISTITEM>
<PARA>
Message returned if successfully.
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-RESET-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
The RESET statement restores variables to the default values.
Refer to the SET command for details on allowed values and defaults.
RESET is an alternate form for
<synopsis>
<command>SET <replaceable class="parameter">variable</replaceable> = DEFAULT</command>
</synopsis>
<REFSECT2 ID="R2-SQL-RESET-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
The RESET statement is a <productname>Postgres</productname> language extension.
<para>
Refer to SET/SHOW statements to set/show variable values.
</REFSECT2>
</refsect1>
<REFSECT1 ID="R1-SQL-RESET-2">
<TITLE>
Usage
</TITLE>
<PARA>
<ProgramListing>
-- reset DateStyle to its default;
RESET DateStyle;
</programlisting>
<programlisting>
-- reset Geqo to its default;
RESET GEQO;
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-RESET-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-RESET-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
There is no RESET statement in SQL92.
</REFENTRY>
<!--
<REPLACEABLE CLASS="PARAMETER">
</REPLACEABLE>
<ReturnValue></ReturnValue>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>&bull;
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
<PARA>
</PARA>
-->
doc/src/sgml/ref/revoke.sgml 0 → 100644
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<REFENTRY ID="SQL-REVOKE">
<REFMETA>
<REFENTRYTITLE>
REVOKE
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
REVOKE
</REFNAME>
<REFPURPOSE>
Revokes access privilege from a user, a group or all users.
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-09-01</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
<REPLACEABLE CLASS="PARAMETER">
</REPLACEABLE>
REVOKE <REPLACEABLE CLASS="PARAMETER">privilege</REPLACEABLE> [, ...]
ON <REPLACEABLE CLASS="PARAMETER">object</REPLACEABLE> [, ...]
FROM { PUBLIC | GROUP <REPLACEABLE CLASS="PARAMETER">group</REPLACEABLE> | <REPLACEABLE CLASS="PARAMETER">username</REPLACEABLE> }
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-REVOKE-1">
<REFSECT2INFO>
<DATE>1998-09-01</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">privilege</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
The possible privileges are:
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
SELECT
</TERM>
<LISTITEM>
<PARA>
Privilege to access all of the columns of a specific
table/view.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
INSERT
</TERM>
<LISTITEM>
<PARA>
Privilege to insert data into all columns of a
specific table.
<VARLISTENTRY>
<TERM>
UPDATE
</TERM>
<LISTITEM>
<PARA>
Privilege to update all columns of a specific
table.
<VARLISTENTRY>
<TERM>
DELETE
</TERM>
<LISTITEM>
<PARA>
Privilege to delete rows from a specific table.
<VARLISTENTRY>
<TERM>
RULE
</TERM>
<LISTITEM>
<PARA>
Privilege to define rules on table/view.
(See the <command>CREATE RULE</command> statement).
<VARLISTENTRY>
<TERM>
ALL
</TERM>
<LISTITEM>
<PARA>
Rescind all privileges.
</VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">object</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
The name of an object from which to revoke access.
The possible objects are:
<simplelist>
<member>
table
<member>
view
<member>
sequence
<member>
index
</simplelist>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">group</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
The name of a group from whom to revoke privileges.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">username</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
The name of a user from whom revoke privileges. Use the PUBLIC keyword
to specify all users.
</PARA>
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
PUBLIC
</TERM>
<LISTITEM>
<PARA>
Rescind the specified privilege(s) for all users.
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-REVOKE-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
CHANGE
</TERM>
<LISTITEM>
<PARA>
Message returned if successfully.
<VARLISTENTRY>
<TERM>
ERROR
</TERM>
<LISTITEM>
<PARA>
Message returned if object is not available or impossible
to revoke privileges from a group or users.
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-REVOKE-1">
<REFSECT1INFO>
<DATE>1998-09-01</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
REVOKE allows creator of an object to revoke permissions granted
before, from all users (via PUBLIC) or a certain user or group.
<REFSECT2 ID="R2-SQL-REVOKE-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
Refer to psql \z command for further information about permissions
on existing objects:
<programlisting>
Database = lusitania
+------------------+---------------------------------------------+
| Relation | Grant/Revoke Permissions |
+------------------+---------------------------------------------+
| mytable | {"=rw","miriam=arwR","group todos=rw"} |
+------------------+---------------------------------------------+
Legend:
uname=arwR -- privileges granted to a user
group gname=arwR -- privileges granted to a GROUP
=arwR -- privileges granted to PUBLIC
r -- SELECT
w -- UPDATE/DELETE
a -- INSERT
R -- RULE
arwR -- ALL
</programlisting>
<tip>
<para>
Currently, to create a GROUP you have to insert
data manually into table pg_group as:
<programlisting>
INSERT INTO pg_group VALUES ('todos');
CREATE USER miriam IN GROUP todos;
</programlisting>
</tip>
</REFSECT2>
<REFSECT1 ID="R1-SQL-REVOKE-2">
<TITLE>
Usage
</TITLE>
<PARA>
<ProgramListing>
-- revoke insert privilege from all users on table films:
--
REVOKE INSERT ON films FROM PUBLIC;
-- revoke all privileges from user manuel on view kinds:
--
REVOKE ALL ON kinds FROM manuel;
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-REVOKE-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-REVOKE-4">
<REFSECT2INFO>
<DATE>1998-09-01</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
The SQL92 syntax for REVOKE has additional capabilities for rescinding
privileges, including those on individual columns in tables:
<variablelist>
<varlistentry>
<term>
<synopsis>
REVOKE { SELECT | DELETE | USAGE | ALL PRIVILEGES } [, ...]
ON <replaceable class="parameter">object</replaceable>
FROM { PUBLIC | <replaceable class="parameter">username</replaceable> [, ...] } { RESTRICT | CASCADE }
REVOKE { INSERT | UPDATE | REFERENCES } [, ...] [ ( <replaceable class="parameter">column</replaceable> [, ...] ) ]
ON <replaceable class="parameter">object</replaceable>
FROM { PUBLIC | <replaceable class="parameter">username</replaceable> [, ...] } { RESTRICT | CASCADE }
</synopsis>
<listitem>
<para>
Refer to the <command>GRANT</command> command for details on individual fields.
<varlistentry>
<term>
<synopsis>
REVOKE GRANT OPTION FOR <replaceable class="parameter">privilege</replaceable> [, ...]
ON <replaceable class="parameter">object</replaceable>
FROM { PUBLIC | <replaceable class="parameter">username</replaceable> [, ...] } { RESTRICT | CASCADE }
</synopsis>
<listitem>
<para>
Rescinds authority for a user to grant the specified privilege to others.
Refer to the <command>GRANT</command> command for details on individual fields.
</variablelist>
<para>
The possible objects are:
<simplelist>
<member> [ TABLE ] table/view
<member> CHARACTER SET character-set
<member> COLLATION collation
<member> TRANSLATION translation
<member> DOMAIN domain
</simplelist>
<para>
If user1 gives a privilege WITH GRANT OPTION to user2,
and user2 gives it to user3 then user1 can revoke
this privilege in cascade using the CASCADE keyword.
If user1 gives a privilege WITH GRANT OPTION to user2,
and user2 gives it to user3 then if user1 try revoke
this privilege it fails if he/she specify the RESTRICT
keyword.
</REFENTRY>
<!--
<REPLACEABLE CLASS="PARAMETER">
</REPLACEABLE>
<ReturnValue></ReturnValue>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>&bull;
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
<PARA>
</PARA>
-->
doc/src/sgml/ref/rollback.sgml 0 → 100644
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<REFENTRY ID="SQL-ROLLBACK">
<REFMETA>
<REFENTRYTITLE>
ROLLBACK
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
ROLLBACK
</REFNAME>
<REFPURPOSE>
Aborts the current transaction
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-09-01</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
ROLLBACK [ WORK ]
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-ROLLBACK-1">
<REFSECT2INFO>
<DATE>1998-09-01</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
None.
</REFSECT2>
<REFSECT2 ID="R2-SQL-ROLLBACK-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
ABORT
</TERM>
<LISTITEM>
<PARA>
Message returned if successful.
<VARLISTENTRY>
<TERM>
NOTICE: UserAbortTransactionBlock and not in in-progress state
ABORT
</TERM>
<LISTITEM>
<PARA>
If there is not any transaction currently in progress.
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-ROLLBACK-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
ROLLBACK rolls back the current transaction and causes
all the updates made by the transaction to be discarded.
<REFSECT2 ID="R2-SQL-ROLLBACK-3">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
The keyword WORK is noise and can be omitted.
<para>
Use the COMMIT statement to successfully terminate a transaction.
</REFSECT1>
<REFSECT1 ID="R1-SQL-ROLLBACK-2">
<TITLE>
Usage
</TITLE>
<PARA>
<ProgramListing>
--To abort all changes:
--
ROLLBACK WORK;
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-ROLLBACK-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-ROLLBACK-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
Full compatibility.
</REFENTRY>
<!--
<REPLACEABLE CLASS="PARAMETER">
</REPLACEABLE>
<ReturnValue></ReturnValue>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>&bull;
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
<PARA>
</PARA>
-->
doc/src/sgml/ref/select.sgml
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......@@ -188,6 +188,9 @@ The count of rows returned by the query.
Description
</TITLE>
<PARA>
SELECT is the principal means to access information
in <productname>Postgres</productname>.
SELECT will get all rows which satisfy the WHERE condition
or all rows of a table if WHERE is omitted.
......@@ -195,17 +198,14 @@ Description
The GROUP BY clause allows a user to divide a table
conceptually into groups. (See GROUP BY clause).
<PARA>
The HAVING clause specifies a grouped table derived by the
elimination of groups from the result of the previously
specified clause. (See HAVING clause).
<PARA>
The ORDER BY clause allows a user to specify that he/she
wishes the rows sorted according to the ASCending or
DESCending mode operator. (See ORDER BY clause)
<PARA>
The UNION clause specifies a table derived from a Cartesian
product union join. (See UNION clause).
......
doc/src/sgml/ref/set.sgml 0 → 100644
浏览文件 @ 1660e300
<REFENTRY ID="SQL-SET">
<REFMETA>
<REFENTRYTITLE>
SET
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
SET
</REFNAME>
<REFPURPOSE>
Set run-time parameters for session
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-08-31</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
<REPLACEABLE CLASS="PARAMETER">
</REPLACEABLE>
SET <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE> { TO | = } { '<REPLACEABLE CLASS="PARAMETER">value</REPLACEABLE>' | DEFAULT }
SET TIME ZONE { '<REPLACEABLE CLASS="PARAMETER">timezone</REPLACEABLE>' | LOCAL };
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-SET-1">
<REFSECT2INFO>
<DATE>1998-08-31</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE>
</TERM>
<LISTITEM>
<para>
Settable global parameter.
<varlistentry>
<term>
<REPLACEABLE CLASS="PARAMETER">value</REPLACEABLE>
</term>
<listitem>
<PARA>
New value of parameter.
</variablelist>
<para>
The possible variables and allowed values are:
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
DateStyle
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
ISO
</TERM>
<LISTITEM>
<PARA>
use ISO 8601-style dates and times
<VARLISTENTRY>
<TERM>
SQL
</TERM>
<LISTITEM>
<PARA>
use Oracle/Ingres-style dates and times
<VARLISTENTRY>
<TERM>
Postgres
</TERM>
<LISTITEM>
<PARA>
use traditional <productname>Postgres</productname> format
<VARLISTENTRY>
<TERM>
European
</TERM>
<LISTITEM>
<PARA>
use dd/mm/yyyy for numeric date representations.
<VARLISTENTRY>
<TERM>
NonEuropean
</TERM>
<LISTITEM>
<PARA>
use mm/dd/yyyy for numeric date representations.
<VARLISTENTRY>
<TERM>
German
</TERM>
<LISTITEM>
<PARA>
use dd.mm.yyyy for numeric date representations.
<VARLISTENTRY>
<TERM>
US
</TERM>
<LISTITEM>
<PARA>
same as 'NonEuropean'
<VARLISTENTRY>
<TERM>
default
</TERM>
<LISTITEM>
<PARA>
restores the default values ('US,Postgres')
</varlistentry>
</variablelist>
<para>
Date format initialization my be done by:
<simplelist>
<member>
Setting PGDATESTYLE environment variable.
<member>
Running postmaster using -oe parameter to set
dates to the 'European' convention.
Note that this affects only the some combinations of date styles; for example
the ISO style is not affected by this parameter.
<member>
Changing variables in
<filename>src/backend/utils/init/globals.c</filename>.
</simplelist>
<para>
The variables in <filename>globals.c</filename> which can be changed are:
<programlisting>
bool EuroDates = false
true
int DateStyle = USE_ISO_DATES
USE_POSTGRES_DATES
USE_ISO_DATES
USE_SQL_DATES
USE_GERMAN_DATES
</programlisting>
</varlistentry>
<varlistentry>
<term>
TIMEZONE
</term>
<listitem>
<para>
The possible values for timezone depends on your operating
system. For example on Linux /usr/lib/zoneinfo contains the
database of timezones.
<para>
Here are some valid values for timezone:
<variablelist>
<varlistentry>
<term>
'PST8PDT'
</term>
<listitem>
<para>
set the timezone for California
<varlistentry>
<term>
'Portugal'
</term>
<listitem>
<para>
set time zone for Portugal.
<varlistentry>
<term>
'Europe/Rome'
</term>
<listitem>
<para>
set time zone for Italy.
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
set time zone to your local timezone
(value of the TZ environment variable).
</variablelist>
<para>
If an invalid time zone is specified, the time zone
becomes GMT (on most systems anyway).
<para>
A frontend which uses libpq may be initialized by setting the PGTZ
environment variable.
<para>
The second syntax shown above, allows one to set the timezone
with a syntax similar to SQL92 <command>SET TIME ZONE</command>.
The LOCAL keyword is just an alternate form
of DEFAULT for SQL92 compatibility.
</varlistentry>
</variablelist>
There are also several internal or optimization parameters which can be specified
by the <command>SET</command> command:
<variablelist>
<varlistentry>
<term>
COST_HEAP
</term>
<listitem>
<para>
Sets the default cost of a heap scan for use by the optimizer.
<variablelist>
<varlistentry>
<term>
<replaceable class="parameter">float4</replaceable>
</term>
<listitem>
<para>
Set the cost of a heap scan to the specified floating point value.
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Sets the cost of a heap scan to the default value.
</variablelist>
<para>
The frontend may be initialized by setting the PGCOSTHEAP
environment variable.
<varlistentry>
<term>
COST_INDEX
</term>
<listitem>
<para>
Sets the default cost of an index scan for use by the optimizer.
<variablelist>
<varlistentry>
<term>
<replaceable class="parameter">float4</replaceable>
</term>
<listitem>
<para>
Set the cost of an index scan to the specified floating point value.
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Sets the cost of an index scan to the default value.
</variablelist>
<para>
The frontend may be initialized by setting the PGCOSTINDEX
environment variable.
<varlistentry>
<term>
GEQO
</term>
<listitem>
<para>
Sets the threshold for using the genetic optimizer algorithm.
<variablelist>
<varlistentry>
<term>
On
</term>
<listitem>
<para>
enables the genetic optimizer algorithm
for statements with 8 or more tables.
<varlistentry>
<term>
On=#
</term>
<listitem>
<para>
enables the genetic optimizer algorithm
for statements with # or more tables.
<varlistentry>
<term>
Off
</term>
<listitem>
<para>
disables the genetic optimizer algorithm.
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Equivalent to specifying <command>SET GEQO=On</command>
</varlistentry>
</variablelist>
<para>
This algorithm is on by default, which used GEQO for
statements of eight or more tables.
(See the chapter on GEQO in the Programmer's Guide
for more information).
<para>
The frontend may be initialized by setting PGGEQO
environment variable.
</varlistentry>
<varlistentry>
<term>
R_PLANS
</term>
<listitem>
<para>
Determines whether right-hand plan evaluation is allowed:
<variablelist>
<varlistentry>
<term>
On
</term>
<listitem>
<para>
enables right-hand evaluation of plans.
<varlistentry>
<term>
Off
</term>
<listitem>
<para>
disables right-hand evaluation of plans.
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Equivalent to specifying <command>SET R_PLANS=Off</command>.
</variablelist>
<para>
It may be useful when joining big relations with
small ones. This algorithm is off by default.
It's not used by GEQO anyway.
<para>
The frontend may be initialized by setting the PGRPLANS
environment variable.
</varlistentry>
<varlistentry>
<term>
R_PLANS
</term>
<listitem>
<para>
Determines whether right-hand plan evaluation is allowed:
<variablelist>
<varlistentry>
<term>
On
</term>
<listitem>
<para>
enables right-hand evaluation of plans.
<varlistentry>
<term>
Off
</term>
<listitem>
<para>
disables right-hand evaluation of plans.
<varlistentry>
<term>
DEFAULT
</term>
<listitem>
<para>
Equivalent to specifying <command>SET R_PLANS=Off</command>.
</variablelist>
<para>
It may be useful when joining big relations with
small ones. This algorithm is off by default.
It's not used by GEQO anyway.
<para>
The frontend may be initialized by setting the PGRPLANS
environment variable.
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-SET-2">
<REFSECT2INFO>
<DATE>1998-08-31</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
SET VARIABLE
</TERM>
<LISTITEM>
<PARA>
Message returned if successfully.
<VARLISTENTRY>
<TERM>
WARN: Bad value for <replaceable class="parameter">variable</replaceable> (<replaceable class="parameter">value</replaceable>)
</TERM>
<LISTITEM>
<PARA>
If fails to set variable.
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-SET-1">
<REFSECT1INFO>
<DATE>1998-08-31</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
SET will modify configuration parameters for variable during
a session.
<para>
Current values can be obtained using SHOW statement, and values
can be restored to the defaults using RESET statement.
Parameters and values are case-insensitive. Note that the value
field is always specified as a string, so is enclosed in
single-quotes.
<para>
SET TIME ZONE changes the session's default time zone offset.
A SQL-session always begins with an initial default time zone
offset.
The SET TIME ZONE statement is used to change the default
time zone offset for the current SQL session.
<REFSECT2 ID="R2-SQL-SET-3">
<REFSECT2INFO>
<DATE>1998-08-31</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
The <command>SET <replaceable class="parameter">variable</replaceable></command>
statement is a <productname>Postgres</productname> language extension.
<para>
Refer to SHOW/RESET statements to show/reset variable values.
</REFSECT2>
</REFSECT1>
<REFSECT1 ID="R1-SQL-SET-2">
<TITLE>
Usage
</TITLE>
<PARA>
</PARA>
<ProgramListing>
--Set the style of date to ISO:
--
SET DATESTYLE TO 'ISO';
</programlisting>
<programlisting>
--Set GEQO to default:
--
SET GEQO = DEFAULT;
</programlisting>
<programlisting>
--Turn on right-hand evaluation of plans:
--
SET R_PLANS TO 'on';
</programlisting>
<programlisting>
--set the timezone for Berkeley, California:
SET TIME ZONE 'PST8PDT';
SELECT CURRENT_TIMESTAMP AS today;
today
----------------------
1998-03-31 07:41:21-08
</programlisting>
<programlisting>
--set the timezone for Italy:
SET TIME ZONE 'Europe/Rome';
SELECT CURRENT_TIMESTAMP AS today;
today
----------------------
1998-03-31 17:41:31+02
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-SET-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-SET-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
There is no
<command>SET <replaceable class="parameter">variable</replaceable></command>
in SQL92.
The SQL92 syntax for SET TIME ZONE is slightly different,
allowing only a single integer value for time zone specification:
<programlisting>
SET TIME ZONE { interval_value_expression | LOCAL }
</programlisting>
</REFENTRY>
<!--
<REPLACEABLE CLASS="PARAMETER">
</REPLACEABLE>
<ReturnValue></ReturnValue>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>&bull;
</TERM>
<LISTITEM>
<PARA>
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
<PARA>
</PARA>
-->
doc/src/sgml/ref/show.sgml 0 → 100644
浏览文件 @ 1660e300
<REFENTRY ID="SQL-SHOW">
<REFMETA>
<REFENTRYTITLE>
SHOW
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
SHOW
</REFNAME>
<REFPURPOSE>
Shows run-time parameters for session
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-08-31</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
SHOW <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE>
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-SHOW-1">
<REFSECT2INFO>
<DATE>1998-08-31</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
Refer to the SET statement for more information on available
variables.
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-SHOW-2">
<REFSECT2INFO>
<DATE>1998-08-31</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
NOTICE: <REPLACEABLE CLASS="PARAMETER">variable</REPLACEABLE> is <ReturnValue>value</ReturnValue>
SHOW VARIABLE
</TERM>
<LISTITEM>
<PARA>
Message returned if successfully.
</listitem>
<VARLISTENTRY>
<TERM>
NOTICE: Unrecognized variable <ReturnValue>value</ReturnValue>
<LISTITEM>
<PARA>
Message returned if <ReturnValue>value</ReturnValue> does not exist.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-SHOW-1">
<REFSECT1INFO>
<DATE>1998-08-31</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
SHOW will display the current configuration parameters for
variable during a session.
<para>
The session can be configured using SET statement, and values
can be restored to the defaults using RESET statement.
Parameters and values are case-insensitive.
<REFSECT2 ID="R2-SQL-SHOW-3">
<REFSECT2INFO>
<DATE>1998-08-31</DATE>
</REFSECT2INFO>
<TITLE>
Notes
</TITLE>
<PARA>
The SHOW statement is a <productname>Postgres</productname>
language extension.
<para>
Refer to the SET/RESET statements to set/reset variable values.
See also the SET TIME ZONE statement.
<para>
If the TZ environment variable is not set the SHOW TIME ZONE statement
gives the message: Time zone is unknown
</REFSECT2>
</REFSECT1>
<REFSECT1 ID="R1-SQL-SHOW-2">
<TITLE>
Usage
</TITLE>
<PARA>
<ProgramListing>
-- show DateStyle;
SHOW DateStyle;
NOTICE:DateStyle is Postgres with US (NonEuropean) conventions
-- show Geqo;
SHOW GEQO;
NOTICE:GEQO is ON
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-SHOW-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-SHOW-4">
<REFSECT2INFO>
<DATE>1998-08-31</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
There is no SET statement defined in <acronym>SQL92</acronym>.
</refsect2>
</refsect1>
</REFENTRY>
doc/src/sgml/ref/update.sgml 0 → 100644
浏览文件 @ 1660e300
<REFENTRY ID="SQL-UPDATE">
<REFMETA>
<REFENTRYTITLE>
UPDATE
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
UPDATE
</REFNAME>
<REFPURPOSE>
Replaces values of columns in a table
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-04-15</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
UPDATE <REPLACEABLE CLASS="PARAMETER">table</replaceable> SET <REPLACEABLE CLASS="PARAMETER">column</replaceable> = <REPLACEABLE CLASS="PARAMETER">expression</replaceable> [, ...]
[FROM <REPLACEABLE CLASS="PARAMETER">fromlist</REPLACEABLE>]
[WHERE <REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE>]
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-UPDATE-1">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">table</replaceable>
</TERM>
<LISTITEM>
<PARA>
The name of an existing table.
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">column</replaceable>
</TERM>
<LISTITEM>
<PARA>
The name of a column in <REPLACEABLE CLASS="PARAMETER">table</replaceable>.
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">expression</replaceable>
</TERM>
<LISTITEM>
<PARA>
A valid expression or value to assign to column.
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">fromlist</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
A <productname>Postgres</productname>
non-standard extension to allow columns
from other tables to appear in the WHERE condition.
</LISTITEM>
</VARLISTENTRY>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">condition</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
Refer to the SELECT statement for a further description
of the WHERE clause.
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-UPDATE-2">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
UPDATE <replaceable class="parameter">#</replaceable>
</TERM>
<LISTITEM>
<PARA>
Message returned if successful.
The <replaceable class="parameter">#</replaceable>
means the number of rows updated.
If <replaceable class="parameter">#</replaceable>
is equal 0 no rows are updated.
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-UPDATE-1">
<REFSECT1INFO>
<DATE>1998-04-15</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
UPDATE changes the values of the columns specified for
all rows which satisfy condition. Only the columns
to be modified need appear as column.
<PARA>
Array references use the same syntax found in SELECT.
That is, either single array elements, a range of array
elements or the entire array may be replaced with a single
query.
<PARA>
You must have write access to the table in order to modify
it, as well as read access to any table whose values are
mentioned in the WHERE condition.
</REFSECT1>
<REFSECT1 ID="R1-SQL-UPDATE-2">
<TITLE>
Usage
</TITLE>
<PARA>
</PARA>
<ProgramListing>
--Change word "Drama" with "Dramatic" on column kind:
--
UPDATE films
SET kind = 'Dramatic'
WHERE kind = 'Drama';
SELECT * FROM films WHERE kind = 'Dramatic' OR kind = 'Drama';
code |title |did| date_prod|kind |len
-----+-------------+---+----------+----------+------
BL101|The Third Man|101|1949-12-23|Dramatic | 01:44
P_302|Becket |103|1964-02-03|Dramatic | 02:28
M_401|War and Peace|104|1967-02-12|Dramatic | 05:57
T_601|Yojimbo |106|1961-06-16|Dramatic | 01:50
DA101|Das Boot |110|1981-11-11|Dramatic | 02:29
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-UPDATE-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
</PARA>
<REFSECT2 ID="R2-SQL-UPDATE-4">
<REFSECT2INFO>
<DATE>1998-04-15</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
SQL92 defines a different syntax for positioned UPDATE statement:
<programlisting>
UPDATE table SET column = expression [, ...]
WHERE CURRENT OF <replaceable class="parameter">cursor</replaceable>
</programlisting>
where <replaceable class="parameter">cursor</replaceable>
identifies an open cursor.
</REFENTRY>
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