Return Value
A System.Data.DataTable that describes the column metadata.
| 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 System.Data.DbType is a numeric data type, this is the maximum precision of the column. The precision depends on the definition of the column. If System.Data.DbType is not a numeric data type, this is a null value. |
| NumericScale | If System.Data.DbType is Decimal, the number of digits to the right of the decimal point. Otherwise, this is a null value. |
| DataType | Maps to the .Net Framework type of the column. |
| ProviderType | The indicator of the column's data type. |
| IsLong | true if the column contains a bytea 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. |
| IsReadOnly | true if the column can be modified; otherwise, false. |
| IsRowVersion | Set if the column contains a persistent row identifier that cannot be written to, and has no meaningful value except to identity the row. |
| 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. |
| IsAutoIncrement | true if the column assigns values to new rows in fixed increments; otherwise, false. The default value for this column is false. |
| BaseSchemaName | The name of the schema in the database that contains the column. NULL if the base catalog name cannot be determined. The default for this column is a null value. |
| BaseCatalogName | The name of the catalog in the data store that contains the column. NULL if the base catalog name cannot be determined. The default value for this column is a null value. |
| 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 value 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 value for this column is a null value. |
| IsAliased | true if the column name is an alias; otherwise, false. |
| IsExpression | true if the column is an expression; otherwise, false. |