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OracleDataReader.GetSchemaTable Method

Note: This namespace, class, or member is supported only in version 1.1 of the .NET Framework.

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

[Visual Basic]
Public Overridable Function GetSchemaTable() As DataTable Implements _
   IDataReader.GetSchemaTable
[C#]
public virtual DataTable GetSchemaTable();
[C++]
public: virtual DataTable* GetSchemaTable();
[JScript]
public function GetSchemaTable() : DataTable;

Return Value

A DataTable that describes the column metadata.

Implements

IDataReader.GetSchemaTable

Exceptions

Exception Type Condition
InvalidOperationException The OracleDataReader is closed.

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 ordinal of the column. This is zero for the bookmark column of the row, if any. Other columns are numbered starting with 1. 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.
NumericScale If DbType is a numeric data type, the number of digits to the right of the decimal point.
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 will be 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.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

.NET Framework Security: 

See Also

OracleDataReader Class | OracleDataReader Members | System.Data.OracleClient Namespace

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