@@ -45,7 +45,7 @@ In TDengine, the data types below can be used when specifying a column or tag.
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@@ -45,7 +45,7 @@ In TDengine, the data types below can be used when specifying a column or tag.
:::note
:::note
- Only ASCII visible characters are suggested to be used in a column or tag of BINARY type. Multi-byte characters must be stored in NCHAR type.
- Only ASCII visible characters are suggested to be used in a column or tag of BINARY type. Multi-byte characters must be stored in NCHAR type.
- The length of BINARY can be up to 16,374 bytes. The string value must be quoted with single quotes. You must specify a length in bytes for a BINARY value, for example binary(20) for up to twenty single-byte characters. If the data exceeds the specified length, an error will occur. The literal single quote inside the string must be preceded with back slash like `\'`
- The length of BINARY can be up to 16,374(data column is 65,517 and tag column is 16,382 since version 3.0.5.0) bytes. The string value must be quoted with single quotes. You must specify a length in bytes for a BINARY value, for example binary(20) for up to twenty single-byte characters. If the data exceeds the specified length, an error will occur. The literal single quote inside the string must be preceded with back slash like `\'`
- Numeric values in SQL statements will be determined as integer or float type according to whether there is decimal point or whether scientific notation is used, so attention must be paid to avoid overflow. For example, 9999999999999999999 will be considered as overflow because it exceeds the upper limit of long integer, but 9999999999999999999.0 will be considered as a legal float number.
- Numeric values in SQL statements will be determined as integer or float type according to whether there is decimal point or whether scientific notation is used, so attention must be paid to avoid overflow. For example, 9999999999999999999 will be considered as overflow because it exceeds the upper limit of long integer, but 9999999999999999999.0 will be considered as a legal float number.
1. The first column of a table MUST be of type TIMESTAMP. It is automatically set as the primary key.
1. The first column of a table MUST be of type TIMESTAMP. It is automatically set as the primary key.
2. The maximum length of the table name is 192 bytes.
2. The maximum length of the table name is 192 bytes.
3. The maximum length of each row is 48k bytes, please note that the extra 2 bytes used by each BINARY/NCHAR column are also counted.
3. The maximum length of each row is 48k(64k since version 3.0.5.0) bytes, please note that the extra 2 bytes used by each BINARY/NCHAR column are also counted.
4. The name of the subtable can only consist of characters from the English alphabet, digits and underscore. Table names can't start with a digit. Table names are case insensitive.
4. The name of the subtable can only consist of characters from the English alphabet, digits and underscore. Table names can't start with a digit. Table names are case insensitive.
5. The maximum length in bytes must be specified when using BINARY or NCHAR types.
5. The maximum length in bytes must be specified when using BINARY or NCHAR types.
6. Escape character "\`" can be used to avoid the conflict between table names and reserved keywords, above rules will be bypassed when using escape character on table names, but the upper limit for the name length is still valid. The table names specified using escape character are case sensitive.
6. Escape character "\`" can be used to avoid the conflict between table names and reserved keywords, above rules will be bypassed when using escape character on table names, but the upper limit for the name length is still valid. The table names specified using escape character are case sensitive.
@@ -26,7 +26,7 @@ The following characters cannot occur in a password: single quotation marks ('),
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@@ -26,7 +26,7 @@ The following characters cannot occur in a password: single quotation marks ('),
- Maximum length of database name is 64 bytes
- Maximum length of database name is 64 bytes
- Maximum length of table name is 192 bytes, excluding the database name prefix and the separator.
- Maximum length of table name is 192 bytes, excluding the database name prefix and the separator.
- Maximum length of each data row is 48K bytes. Note that the upper limit includes the extra 2 bytes consumed by each column of BINARY/NCHAR type.
- Maximum length of each data row is 48K(64K since version 3.0.5.0) bytes. Note that the upper limit includes the extra 2 bytes consumed by each column of BINARY/NCHAR type.
- The maximum length of a column name is 64 bytes.
- The maximum length of a column name is 64 bytes.
- Maximum number of columns is 4096. There must be at least 2 columns, and the first column must be timestamp.
- Maximum number of columns is 4096. There must be at least 2 columns, and the first column must be timestamp.
@@ -90,7 +90,7 @@ You can configure smlChildTableName in taos.cfg to specify table names, for exam
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@@ -90,7 +90,7 @@ You can configure smlChildTableName in taos.cfg to specify table names, for exam
Note: TDengine 3.0.3.0 and later automatically detect whether order is consistent. This parameter is no longer used.
Note: TDengine 3.0.3.0 and later automatically detect whether order is consistent. This parameter is no longer used.
:::tip
:::tip
All processing logic of schemaless will still follow TDengine's underlying restrictions on data structures, such as the total length of each row of data cannot exceed 48 KB and the total length of a tag value cannot exceed 16 KB. See [TDengine SQL Boundary Limits](/taos-sql/limit) for specific constraints in this area.
All processing logic of schemaless will still follow TDengine's underlying restrictions on data structures, such as the total length of each row of data cannot exceed 48 KB(64 KB since version 3.0.5.0) and the total length of a tag value cannot exceed 16 KB. See [TDengine SQL Boundary Limits](/taos-sql/limit) for specific constraints in this area.