COLUMNPROPERTY (Transact-SQL)

id

Is an expression that contains the identifier (ID) of the table or procedure.

column

Is an expression that contains the name of the column or parameter.

property

Is an expression that contains the information to be returned for id, and can be any one of the following values.

Value	Description	Value returned
AllowsNull	Allows null values.	1 = TRUE 0 = FALSE NULL = Input is not valid.
ColumnId	Column ID value corresponding to sys.columns.column_id.	Column ID When querying multiple columns, gaps may appear in the sequence of Column ID values. Note:
FullTextTypeColumn	The TYPE COLUMN in the table that holds the document type information of the column.	ID of the full-text TYPE COLUMN for the column passed as the second parameter of this property.
IsComputed	Column is a computed column.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsCursorType	Procedure parameter is of type CURSOR.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsDeterministic	Column is deterministic. This property applies only to computed columns and view columns.	1 = TRUE 0 = FALSE NULL = Input is not valid. Not a computed column or view column.
IsFulltextIndexed	Column has been registered for full-text indexing.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsIdentity	Column uses the IDENTITY property.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsIdNotForRepl	Column checks for the IDENTITY_INSERT setting. If IDENTITY NOT FOR REPLICATION is specified, the IDENTITY_INSERT setting is not checked.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsIndexable	Column can be indexed.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsOutParam	Procedure parameter is an output parameter.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsPrecise	Column is precise. This property applies only to deterministic columns.	1 = TRUE 0 = FALSE NULL = Input is not valid. Not a deterministic column
IsRowGuidCol	Column has the uniqueidentifier data type and is defined with the ROWGUIDCOL property.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsSystemVerified	The determinism and precision properties of the column can be verified by the SQL Server 2005 Database Engine. This property applies only to computed columns and columns of views.	1 = TRUE 0 = FALSE NULL = Input is not valid.
IsXmlIndexable	The XML column can be used in an XML index	1 = TRUE 0 = FALSE NULL = Input is not valid.
Precision	Length for the data type of the column or parameter.	The length of the specified column data type -1 = xml or large value types NULL = Input is not valid.
Scale	Scale for the data type of the column or parameter.	The scale NULL = Input is not valid.
SystemDataAccess	Column is derived from a function that accesses data in the system catalogs or virtual system tables of SQL Server. This property applies only to computed columns and columns of views.	1 = TRUE (Indicates read-only access.) 0 = FALSE NULL = Input is not valid.
UserDataAccess	Column is derived from a function that accesses data in user tables, including views and temporary tables, stored in the local instance of SQL Server. This property applies only to computed columns and columns of views.	1 = TRUE (Indicates read-only access.) 0 = FALSE NULL = Input is not valid.
UsesAnsiTrim	ANSI_PADDING was set ON when the table was first created. This property applies only to columns or parameters of type char or varchar.	1= TRUE 0= FALSE NULL = Input is not valid.

int

Returns NULL on error or if a caller does not have permission to view the object.

In SQL Server 2005, a user can only view the metadata of securables that the user owns or on which the user has been granted permission. This means that metadata-emitting, built-in functions such as COLUMNPROPERTY may return NULL if the user does not have any permission on the object. For more information, see Metadata Visibility Configuration and Troubleshooting Metadata Visibility.

When you check the deterministic property of a column, first test whether the column is a computed column. IsDeterministic returns NULL for noncomputed columns. Computed columns can be specified as index columns.

The following example returns the length of the LastName column.

USE AdventureWorks;
GO
SELECT COLUMNPROPERTY( OBJECT_ID('Person.Contact'),'LastName','PRECISION')AS 'Column Length';
GO

Here is the result set.

Column Length 
------------- 
50

(1 row(s) affected)

Reference

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