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Metadata Discovery

  • Artikkeli

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW)

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The metadata discovery improvement in SQL Server 2012 (11.x) allows OLE DB Driver for SQL Server applications to ensure that column or parameter metadata returned from the execution of a query is identical to or compatible with the metadata format you specified before you executed the query. You will receive an error if the metadata returned after query execution is not compatible with the metadata format you specified before query execution.

In bcp and IBCPSession and IBCPSession2 interfaces, you can now specify a delayed read (delayed metadata discovery) to avoid metadata discovery for query out operations. This improves performance and eliminates metadata discovery failures.

If you develop an application using OLE DB Driver for SQL Server but connect to a server version earlier than SQL Server 2012 (11.x), metadata discovery functionality will correspond to the version of the server.

Remarks

The following OLE DB member functions have been enhanced in SQL Server 2012 (11.x) to provide improved metadata discovery:

  • IColumnsInfo::GetColumnInfo

  • IColumnsRowset::GetColumnsRowset

  • ICommandWithParameters::GetParameterInfo (see ICommandWithParameters for more information)

You will also see a performance improvement when specifying metadata format using IBCPSession::BCPSetBulkMode

The improved metadata discovery in OLE DB Driver for SQL Server is possible because of the addition of two stored procedures in SQL Server 2012 (11.x):

  • sp_describe_first_result_set

  • sp_describe_undeclared_parameters

See Also

OLE DB Driver for SQL Server Features