OracleDataReader.GetSchemaTable Method

Definition

Namespace:

System.Data.OracleClient

Assembly:

System.Data.OracleClient.dll

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

public:
 override System::Data::DataTable ^ GetSchemaTable();

public override System.Data.DataTable GetSchemaTable ();

override this.GetSchemaTable : unit -> System.Data.DataTable

Public Overrides Function GetSchemaTable () As DataTable

Returns

DataTable

A DataTable that describes the column metadata.

Remarks

The GetSchemaTable method returns metadata about each column in the following order:

DataReader Column	Description
ColumnName	The name of the column; this might not be unique. If the column name cannot be determined, a null value is returned. This name always reflects the most recent naming of the column in the current view or command text.
ColumnOrdinal	The zero-based ordinal of the column. This column cannot contain a null value.
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	If DbType is a numeric data type, this is the maximum precision of the column. The precision depends on the definition of the column. Float and Double data types in Oracle are binary precision.
NumericScale	If DbType is a numeric data type, the number of digits to the right of the decimal point. Float and Double data types in Oracle are binary scale.
DataType	Maps to the common language runtime type of DbType.
IsLong	true if the column contains a Binary Long Object (BLOB) that contains very long data.
AllowDBNull	true if the consumer can set the column to a null value; otherwise, false. A column may contain null values, even if it cannot be set to a null value.
IsUnique	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 true if the column constitutes a key by itself or if there is a constraint of type UNIQUE that applies only to this column. false: The column can contain duplicate values in the base table. The default for this column is false.
IsKey	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 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. false: The column is not required to uniquely identify the row.
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	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 for this column is a null value.
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 for this column is a null value.

A row is returned for every column in the results set.

Note

To ensure that metadata columns return the correct information, you must call ExecuteReader with the behavior parameter set to KeyInfo. Otherwise, some of the columns in the schema table may return default, null, or incorrect data.

See also

• Retrieving Database Schema Information (ADO.NET)