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体验新版 GitCode,发现更多精彩内容 >>
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5f93794f
编写于
1月 22, 2001
作者:
B
Bruce Momjian
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Update FAQ.
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@@ -172,19 +172,23 @@
1.4) What non-unix ports are available?
Client
It is possible to compile the libpq C library, psql, and other
interfaces and binaries to run on MS Windows platforms. In this case,
the client is running on MS Windows, and communicates via TCP/IP to a
server running on one of our supported Unix platforms. A file
win31.mak is included in the distribution for making a Win32 libpq
library and psql.
library and psql.
PostgreSQL also communicates with ODBC clients.
Server
The database server can run on Windows NT and later using Cygwin, the
Cygnus Unix/NT porting library. See pgsql/doc/FAQ_MSWIN in the
distribution
. The database server does not run on MS Windows 9X
because Cygwin does not support the required features on those
platforms. We have no plans to do a native port to any Microsoft
platform.
distribution
or the MS Windows FAQ on our web site. The database
server does not run on MS Windows 9X because Cygwin does not support
the required features on those platforms. We have no plan to do a
native port to any Microsoft
platform.
1.5) Where can I get PostgreSQL?
...
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@@ -310,8 +314,7 @@
key referential integrity, and sophisticated locking. We have
some features they don't have, like user-defined types,
inheritance, rules, and multi-version concurrency control to
reduce lock contention. We don't have outer joins, but are
working on them.
reduce lock contention.
Performance
PostgreSQL runs in two modes. Normal fsync mode flushes every
...
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@@ -759,7 +762,7 @@ Maximum number of indexes on a table? unlimited
4.14) In a query, how do I detect if a field is NULL?
You test the column with IS NULL
and
IS NOT NULL.
You test the column with IS NULLIS NOT NULL.
4.15) What is the difference between the various character types?
...
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@@ -896,9 +899,13 @@ BYTEA bytea variable-length byte array (null-safe)
Depending on your shell, only one of these may succeed, but it will
set your process data segment limit much higher and perhaps allow the
query to complete. This command applies to the current process, and
all subprocesses created after the command is run. If you are having a
problem with the SQL client because the backend is returning too much
data, try it before starting the client.
all subprocessesHTML & CSS specifications are available from
http://www.w3.org/ To learn more about Tidy see
http://www.w3.org/People/Raggett/tidy/ Please send bug reports to Dave
Raggett care of Lobby your company to join W3C, see
http://www.w3.org/Consortium created after the command is run. If you
are having a problem with the SQL client because the backend is
returning too much data, try it before starting the client.
4.20) How do I tell what PostgreSQL version I am running?
...
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@@ -941,10 +948,18 @@ SELECT *
4.24) How do I do an outer join?
PostgreSQL 7.1 and later supports outer joins. In previous releases,
outer joins can be simulated using UNION and NOT IN. For example, when
joining tab1 and tab2, the following query does an outer join of the
two tables:
PostgreSQL 7.1 and later supports outer joins. Here is an example:
SELECT *
FROM t1 LEFT OUTER JOIN t2 USING (col);
This will join t1.col to t2.col, and return any unjoined rows in t1
with NULL values for t2 columns. A RIGHT join would return unjoined
rows of table t2. A FULL join would return unjoined rows from t1 and
t2. The word OUTER is optional and is assumed in LEFT, RIGHT, and FULL
joins. Ordinary joins are called INNER joins.
In previous releases, outer joins can be simulated using UNION and NOT
IN. For example, when joining tab1 and tab2, the following query does
an outer join of the two tables:
SELECT tab1.col1, tab2.col2
FROM tab1, tab2
WHERE tab1.col1 = tab2.col1
...
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doc/src/FAQ/FAQ.html
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