| title | description | author | ms.author | ms.date | ms.service | ms.subservice | ms.topic | helpviewer_keywords | |
|---|---|---|---|---|---|---|---|---|---|
Descriptor Field for Table-Valued Parameter |
Descriptor Fields for Table-Valued Parameter Constituent Columns |
markingmyname |
maghan |
03/14/2017 |
sql |
native-client |
reference |
|
[!INCLUDESQL Server Azure SQL Database Synapse Analytics PDW]
The table-valued parameter descriptor fields described in this section are manipulated by using SQLSetDescField and SQLSetDescField with the handle for the implementation parameter descriptor (IPD).
SQL_DESC_AUTO_UNIQUE_VALUE is used for table-valued parameters as well as other features.
| Attribute name | Type | Description |
|---|---|---|
| SQL_DESC_AUTO_UNIQUE_VALUE | SQLINTEGER | SQL_TRUE indicates that this column is an identity column. [!INCLUDEssNoVersion] can use this information to optimize performance, but applications are not required to set it for identity columns. |
The following attributes are added to all parameter types in the application parameter descriptor (APD) and implementation parameter descriptor (IPD):
| Attribute name | Type | Description |
|---|---|---|
| SQL_CA_SS_COLUMN_COMPUTED | SQLSMALLINT | SQL_TRUE indicates that this column is computed. [!INCLUDEssNoVersion] can use this information to optimize performance, but applications are not required to set it for computed columns. This attribute is ignored for bindings that are not table-valued parameter columns. |
| SQL_CA_SS_COLUMN_IN_UNIQUE_KEY | SQLSMALLINT | SQL_TRUE indicates that a table-valued parameter column participates in a unique key. This can result in better query performance. This attribute is ignored for bindings that are not table-valued parameter columns. |
| SQL_CA_SS_COLUMN_SORT_ORDER | SQLSMALLINT | Indicates the sort order of a table-valued parameter column. This can result in better query performance. This attribute is ignored for bindings that are not table-valued parameter columns. The possible values are the following: SQL_SS_ASCENDING_ORDER SQL_SS_DESCENDING_ORDER SQL_SS_ORDER_UNSPECIFIED Values other than SQL_SS_ASCENDING_ORDER and SQL_SS_DESCENDING_ORDER generate an error with SQLSTATE HY024 and message 'Invalid attribute value' and are treated as SQL_SS_ORDER_UNSPECIFIED, which is the default value for this attribute. |
| SQL_CA_SS_COLUMN_SORT_ORDINAL | SQLSMALLINT | Indicates the ordinal of a table-valued parameter column in the set of columns that define the overall ordering for a table-valued parameter. This can result in better query performance. This attribute is ignored for bindings that are not table-valued parameter columns. Sort ordinals start at 1. A value of 0, the default, indicates that a table-valued parameter column does not have column ordering. |
| SQL_CA_SS_COLUMN_HAS_DEFAULT_VALUE | SQLSMALLINT | Indicates whether all rows in the table-valued parameter will have the default value for this column. For table-valued parameters, it is not possible to select the default value on a row-by-row basis. A value of SQL_FALSE indicates that rows will have non-default values. This is the default. A value of SQL_TRUE indicates that this column will have default values for all rows. If set to SQL_TRUE, no data will be sent to the server. This field can also be used with identity or computed columns if the column values are not required for server processing. |
These attributes are only valid for table-valued parameter columns. They are ignored for other parameters.
If SQL_CA_SS_COL_HAS_DEFAULT_VALUE is set for a table-valued parameter column, SQL_DESC_DATA_PTR for that column must be a null pointer. Otherwise, SQLExecute or SQLExecDirect will return SQL_ERROR. A diagnostic record will be generated with SQLSTATE=07S01 and the message "Invalid use of default parameter for parameter <p>, column <c>", where <p> is the parameter ordinal and <c> is the column ordinal.