DB_SpecialColumns Function

Action

Retrieves the optimal set of columns, which uniquely identifies a row in the specified table, and the columns that are automatically updated when any value in the row is updated by a transaction.

Syntax

hstmnt = DB_SpecialColumns (hdbc, type, catalog-name, schema-name, table-name, scope, nullable)

Variable	Description
`hstmnt`	The returned handle to the executed SQL statement. This is an input parameter for other DBTester functions, for example DB_FetchNext. HSQL.
`hdbc`	The handle to a database as returned by DB_Connect. HDATABASE.
`type`	The type of the column to return. "1" for SQL_BEST_ROWID "2" for SQL_ROWVER STRING.
`catalog-name`	Catalog name for the table. STRING.
`schema-name`	Schema name for the table. STRING.
`table-name`	Table name. STRING.
`scope`	Minimum required scope of the rowid. "0" for SQL_SCOPE_CURROW "1" for SQL_SCOPE_TRANSACTION "2" for SQL_SCOPE_SESSION STRING.
`nullable`	Determines whether or not to return special columns that can have a NULL value. "0" for SQL_NONULLS "1" for SQL_NULLABLE STRING.

Notes

DB_SpecialColumns corresponds to SQLSpecialColumns. For additional information about SQLSpecialColumns, see SQLSpecialColumns Function.

The type argument can have one of the following values.

Value	Description
"1"	SQL_BEST_ROWID returns one ore more optimal columns that allow any row in the specified table to be uniquely identified.
"2"	SQL_ROWVER returns the columns that are automatically updated by the data source when any value in the row is updated by any transaction.

The table-name argument is required. It cannot be an empty string or contain a wildcard.

The following wildcard characters are supported for arguments:

Wildcard character	Matches
%	The percent sign matches any character sequence.
_	The underscore matches any single character.

To omit a variable argument, which is not a required argument, specify the argument as an empty string ("").

The scope argument can have one of the following values:

Value	Meaning	Description
"0"	SQL_SCOPE_CURROW	The rowid is guaranteed to be valid while positioned on the current row.
"1"	SQL_SCOPE_TRANSACTION	The rowid is guaranteed to be valid for the duration of the current transaction.
"2"	SQL_SCOPE_SESSION	The rowid is guaranteed to be valid for the duration of the session, across transaction boundaries.

The nullable argument can have one of the following values.

Value	Meaning	Description
"0"	SQL_NONULLS	Exclude special columns that can have NULL values.
"1"	SQL_NULLABLE	Return special columns even if they can have NULL values.

When you receive a valid statement handle, you can call DB_FetchNext or DB_FetchPrevious to manipulate the information.

Example

[ ] STRING cat, sch, name, ignore
[ ] INTEGER I 
[ ] 
[ ] hstmnt = DB_SpecialColumns (hdbc, "1", cat, sch, " ", "1", "1")
[ ] // retrieve columns and data types; ignore the rest.
[-] while (DB_FetchNext (hstmt, ignore, name, I) == TRUE) {
	[ ] //print columns and data types ...
[-] }