System.Data.OleDb Namespace   OleDbDataReader Class

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Returns a DataTable that describes the column metadata of the OleDbDataReader.

[ VB ]
NotOverridable Public Function GetSchemaTable ( ) As DataTable

[ C# ]
public DataTable GetSchemaTable ( );

[ C++ ]
public: __sealed DataTable GetSchemaTable ( );

[ JScript ]
public function GetSchemaTable ( ) : DataTable

A DataTable that describes the column metadata.

Exception Type	Condition
InvalidOperationException	Occurs when the OleDbDataReader is closed.

The GetSchemaTable method maps to the OLE DB IColumnsRowset::GetColumnsRowset method, and returns metadata about each column in the following order:

DataReader Column	OLE DB Column ID	Description
ColumnName	DBCOLUMN_NAME	The name of the column; this might not be unique. If this cannot be determined, a null value is returned. This name always reflects the most recent renaming of the column in the current view or command text.
ColumnOrdinal	DBCOLUMN_NUMBER	The ordinal of the column. This is zero for the bookmark column of the row, if any. Other columns are numbered starting with one. This column cannot contain a null value.
ColumnSize	DBCOLUMN_COLUMNSIZE	The maximum possible length of a value in the column. For columns that use a fixed-length data type, this is the size of the data type.
NumericPrecision	DBCOLUMN_PRECISION	If DbType is a numeric data type, this is the maximum precision of the column. The precision of columns with a data type of DBTYPE_DECIMAL or DBTYPE_NUMERIC depends on the definition of the column. If DbType is not a numeric data type, this is a null value.
NumericScale	DBCOLUMN_SCALE	If DbType is DBTYPE_DECIMAL or DBTYPE_NUMERIC, this is the number of digits to the right of the decimal point. Otherwise, this is a null value.
DataType	None	Maps to the .Net Framework type of the column.
ProviderType	DBCOLUMN_TYPE	The indicator of the column's data type. If the data type of the column varies from row to row, this must be DBTYPE_VARIANT. This column cannot contain a null value.
IsLong	DBCOLUMNFLAGS_ISLONG	The provider sets DBCOLUMNFLAGS_ISLONG if the column contains a Binary Long Object ( BLOB ) that contains very long data. The definition of very long data is provider-specific. The setting of this flag corresponds to the value of the IS_LONG column in the PROVIDER_TYPES rowset for the data type.
AllowDBNull	DBCOLUMNFLAGS_ISNULLABLE	The provider sets DBCOLUMNFLAGS_ISNULLABLE if the consumer can set the column to a null value, or if the provider cannot determine whether or not the consumer can set the column to a null value. A column may contain null values, even if it cannot be set to a null value.
IsReadOnly	DBCOLUMNFLAGS_WRITE	true if the column can be modified; otherwise false. The column is assumed to be writable if the provider has set either the DBCOLUMNFLAGS_WRITE or DBCOLUMNFLAGS_WRITEUNKNOWN flag.
IsRowVersion	DBCOLUMNFLAGS_ISROWID	The provider sets DBCOLUMNFLAGS_ISROWID if the column contains a persistent row identifier that cannot be written to, and has no meaningful value except to identity the row.
IsUnique	DBCOLUMN_ISUNIQUE	VARIANT_TRUE: No two rows in the base table-the table returned in BaseTableName-can have the same value in this column. IsUnique is guaranteed to be VARIANT_TRUE if the column constitutes a key by itself or if there is a constraint of type UNIQUE that applies only to this column. VARIANT_FALSE: The column can contain duplicate values in the base table.The default of this column is VARIANT_FALSE.
IsKey	DBCOLUMN_KEYCOLUMN	VARIANT_TRUE: The column is one of a set of columns in the rowset that, taken together, uniquely identify the row. The set of columns with IsKey set to VARIANT_TRUE must uniquely identify a row in the rowset. There is no requirement that this set of columns is a minimal set of columns. This set of columns may be generated from a base table primary key, a unique constraint or a unique index. VARIANT_FALSE-The column is not required to uniquely identify the row.
IsAutoIncrement	DBCOLUMN_ISAUTOINCREMENT	VARIANT_TRUE: The column assigns values to new rows in fixed increments. VARIANT_FALSE: The column does not assign values to new rows in fixed increments.The default of this column is VARIANT_FALSE.
BaseSchemaName	DBCOLUMN_BASESCHEMANAME	The name of the schema in the data store that contains the column. A null value if the base schema name cannot be determined. The default of this column is a null value.
BaseCatalogName	DBCOLUMN_BASECATALOGNAME	The name of the catalog in the data store that contains the column. A null value if the base catalog name cannot be determined. The default of this column is a null value.
BaseTableName	DBCOLUMN_BASETABLENAME	The name of the table or view in the data store that contains the column. A null value if the base table name cannot be determined. The default of this column is a null value.
BaseColumnName	DBCOLUMN_BASECOLUMNNAME	The name of the column in the data store. This might be different than the column name returned in the ColumnName column if an alias was used. A null value if the base column name cannot be determined or if the rowset column is derived, but not identical to, a column in the data store. The default of this column is a null value.

OleDbDataReader Members

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