sys.dm_sql_referenced_entities (Transact-SQL)

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SQL Server 2008 Books Online (June 2009)

sys.dm_sql_referenced_entities (Transact-SQL)

Updated: 31 October 2008

Returns one row for each user-defined entity referenced by name in the definition of the specified referencing entity. A dependency between two entities is created when one user-defined entity, called the referenced entity, appears by name in a persisted SQL expression of another user-defined entity, called the referencing entity. For example, if a stored procedure is the specified referencing entity, this function returns all user-defined entities that are referenced in the stored procedure such as tables, views, user-defined types (UDTs), or other stored procedures.

You can use this dynamic management function to report on the following types of entities referenced by the specified referencing entity:

Schema-bound entities
Non-schema-bound entities
Cross-database and cross-server entities
Column-level dependencies on schema-bound and non-schema-bound entities
User-defined types (alias and CLR UDT)
XML schema collections
Partition functions

Syntax

sys.dm_sql_referenced_entities (
        ' [ schema_name. ] referencing_entity_name ' , ' <referencing_class> ' )

<referencing_class> ::=
{
    OBJECT
  | DATABASE_DDL_TRIGGER
  | SERVER_DDL_TRIGGER
}

Arguments

[ schema_name. ] referencing_entity_name

Is the name of the referencing entity. schema_name is required when the referencing class is OBJECT.

schema_name.referencing_entity_name is nvarchar(517).

<referencing_class> ::= { OBJECT | DATABASE_DDL_TRIGGER | SERVER_DDL_TRIGGER }

Is the class of the specified referencing entity. Only one class can be specified per statement.

<referencing_class> is nvarchar(60).

Table Returned

Column name	Data type	Description
referencing_minor_id	int	Column ID when the referencing entity is a column; otherwise 0. Is not nullable.
referenced_server_name	sysname	Name of the server of the referenced entity. This column is populated for cross-server dependencies that are made by specifying a valid four-part name. For information about multipart names, see Transact-SQL Syntax Conventions (Transact-SQL). NULL for non-schema-bound dependencies for which the entity was referenced without specifying a four-part name. NULL for schema-bound entities because they must be in the same database and therefore can only be defined using a two-part (schema.object) name.
referenced_database_name	sysname	Name of the database of the referenced entity. This column is populated for cross-database or cross-server references that are made by specifying a valid three-part or four-part name. NULL for non-schema-bound references when specified using a one-part or two-part name. NULL for schema-bound entities because they must be in the same database and therefore can only be defined using a two-part (schema.object) name.
referenced_schema_name	sysname	Schema in which the referenced entity belongs. NULL for non-schema-bound references in which the entity was referenced without specifying the schema name. Never NULL for schema-bound references.
referenced_entity_name	sysname	Name of the referenced entity. Is not nullable.
referenced_minor_name	sysname	Column name when the referenced entity is a column; otherwise NULL. For example, referenced_minor_name is NULL in the row that lists the referenced entity itself. A referenced entity is a column when a column is identified by name in the referencing entity, or when the parent entity is used in a SELECT * statement.
referenced_id	int	ID of the referenced entity. When referenced_minor_id is not 0, referenced_id is the entity in which the column is defined. Always NULL for cross-server references. NULL for cross-database references when the ID cannot be determined because the database is offline or the entity cannot be bound. NULL for references within the database if the ID cannot be determined. For non-schema-bound references, the ID cannot be resolved in the following cases: The referenced entity does not exist in the database. Name resolution is caller dependent. In this case, is_caller_dependent is set to 1. Never NULL for schema-bound references.
referenced_minor_id	int	Column ID when the referenced entity is a column; otherwise, 0. For example, referenced_minor_is is 0 in the row that lists the referenced entity itself. For non-schema-bound references, column dependencies are reported only when all referenced entities can be bound. If any referenced entity cannot be bound, no column-level dependencies are reported and referenced_minor_id is 0. See Example D.
referenced_class	tinyint	Class of the referenced entity. 1 = Object or column 6 = Type 10 = XML schema collection 21 = Partition function
referenced_class_desc	nvarchar(60)	Description of class of referenced entity. OBJECT_OR_COLUMN TYPE XML_SCHEMA_COLLECTION PARTITION_FUNCTION
is_caller_dependent	bit	Indicates schema binding for the referenced entity occurs at run time; therefore, resolution of the entity ID depends on the schema of the caller. This occurs when the referenced entity is a stored procedure, extended stored procedure, or user-defined function called within an EXECUTE statement. 1 = The referenced entity is caller dependent and is resolved at run time. In this case, referenced_id is NULL. 0 = The referenced entity ID is not caller dependent. Always 0 for schema-bound references and for cross-database and cross-server references that explicitly specify a schema name. For example, a reference to an entity in the format `EXEC MyDatabase.MySchema.MyProc` is not caller dependent. However, a reference in the format `EXEC MyDatabase..MyProc` is caller dependent.
is_ambiguous	bit	Indicates the reference is ambiguous and can resolve at run time to a user-defined function, a user-defined type (UDT), or an xquery reference to a column of type xml. For example, assume the statement `SELECT Sales.GetOrder() FROM Sales.MySales` is defined in a stored procedure. Until the stored procedure is executed, it is not known whether `Sales.GetOrder()` is a user-defined function in the `Sales` schema or column named `Sales` of type UDT with a method named `GetOrder()`. 1 = Reference to a user-defined function or column user-defined type (UDT) method is ambiguous. 0 = Reference is unambiguous or the entity can be successfully bound when the function is called. Always 0 for schema-bound references.

Exceptions

Returns an empty result set under any of the following conditions:

A system object is specified.
The specified entity does not exist in the current database.
The specified entity does not reference any entities.
An invalid parameter is passed.

Returns an error when the specified referencing entity is a numbered stored procedure.

Returns error 2020 when column dependencies cannot be resolved. This error does not prevent the query from returning object-level dependencies. For more information, see Troubleshooting SQL Dependencies.

Remarks

This function can be executed in the context of the any database to return the entities that reference a server-level DDL trigger.

The following table lists the types of entities for which dependency information is created and maintained. Dependency information is not created or maintained for rules, defaults, temporary tables, temporary stored procedures, or system objects.

Entity type	Referencing entity	Referenced entity
Table	Yes*	Yes
View	Yes	Yes
Transact-SQL stored procedure**	Yes	Yes
CLR stored procedure	No	Yes
Transact-SQL user-defined function	Yes	Yes
CLR user-defined function	No	Yes
CLR trigger (DML and DDL)	No	No
Transact-SQL DML trigger	Yes	No
Transact-SQL database-level DDL trigger	Yes	No
Transact-SQL server-level DDL trigger	Yes	No
Extended stored procedures	No	Yes
Queue	No	Yes
Synonym	No	Yes
Type (alias and CLR user-defined type)	No	Yes
XML schema collection	No	Yes
Partition function	No	Yes

* A table is tracked as a referencing entity only when it references a Transact-SQL module, user-defined type, or XML schema collection in the definition of a computed column, CHECK constraint, or DEFAULT constraint.

** Numbered stored procedures with an integer value greater than 1 are not tracked as either a referencing or referenced entity.

For more information, see Understanding SQL Dependencies.

Permissions

Requires SELECT permission on sys.dm_sql_referenced_entities and VIEW DEFINITION permission on the referencing entity. By default, SELECT permission is granted to public. Requires VIEW DEFINITION permission on the database or ALTER DATABASE DDL TRIGGER permission on the database when the referencing entity is a database-level DDL trigger. Requires VIEW ANY DEFINITION permission on the server when the referencing entity is a server-level DDL trigger.

Examples

A. Returning entities that are referenced by a database-level DDL trigger

The following example returns the entities (tables and columns) that are referenced by the database-level DDL trigger ddlDatabaseTriggerLog.

USE AdventureWorks;
GO
SELECT referenced_schema_name, referenced_entity_name, referenced_minor_name, 
    referenced_minor_id, referenced_class_desc
FROM sys.dm_sql_referenced_entities ('ddlDatabaseTriggerLog', 'DATABASE_DDL_TRIGGER');
GO

B. Returning entities that are referenced by an object

The following example returns the entities that are referenced by the user-defined function dbo.ufnGetContactInformation.

USE AdventureWorks;
GO
SELECT referenced_schema_name, referenced_entity_name, referenced_minor_name, 
    referenced_minor_id, referenced_class_desc, is_caller_dependent, is_ambiguous
FROM sys.dm_sql_referenced_entities ('dbo.ufnGetContactInformation', 'OBJECT');
GO

C. Returning column dependencies

The following example creates the table Table1 with the computed column c defined as the sum of columns a and b. The sys.dm_sql_referenced_entities view is then called. The view returns two rows, one for each column defined in the computed column.

USE AdventureWorks;
GO
CREATE TABLE dbo.Table1 (a int, b int, c AS a + b);
GO
SELECT referenced_schema_name AS schema_name,
    referenced_entity_name AS table_name,
    referenced_minor_name AS referenced_column,
    COALESCE(COL_NAME(OBJECT_ID(N'dbo.Table1'),referencing_minor_id), 'N/A') AS referencing_column_name
FROM sys.dm_sql_referenced_entities ('dbo.Table1', 'OBJECT');
GO
-- Remove the table.
DROP TABLE dbo.Table1;
GO

Here is the result set.

schema_name table_name referenced_column referencing_column

----------- ---------- ----------------- ------------------

dbo Table1 a c

dbo Table1 b c

D. Returning non-schema-bound column dependencies

The following example drops Table1 and creates Table2 and stored procedure Proc1. The procedure references Table2 and the nonexistent table Table1. The view sys.dm_sql_referenced_entities is run with the stored procedure specified as the referencing entity. The result set shows one row for Table1 and Table2. Because Table1 does not exist, the column dependencies cannot be resolved and error 2020 is returned.

USE AdventureWorks;
GO
IF OBJECT_ID ( 'dbo.Table1', 'U' ) IS NOT NULL 
    DROP TABLE dbo.Table1;
GO
CREATE TABLE dbo.Table2 (c1 int, c2 int);
GO
CREATE PROCEDURE dbo.Proc1 AS
    SELECT a, b, c FROM Table1;
    SELECT c1, c2 FROM Table2;
GO
SELECT referenced_id, referenced_entity_name AS table_name, referenced_minor_name AS referenced_column_name
FROM sys.dm_sql_referenced_entities ('dbo.Proc1', 'OBJECT');
GO

E. Demonstrating dynamic dependency maintenance

The following example extends Example D to show that dependencies are maintained dynamically. The example first re-creates Table1, which was dropped in Example D. Then sys.dm_sql_referenced_entities is run again with the stored procedure specified as the referencing entity. The result set shows that both tables and their respective columns defined in the stored procedure are returned.

USE AdventureWorks;
GO
CREATE TABLE Table1 (a int, b int, c AS a + b);
GO 
SELECT referenced_id, referenced_entity_name AS table_name, referenced_minor_name as column_name
FROM sys.dm_sql_referenced_entities ('dbo.Proc1', 'OBJECT');
GO
DROP TABLE Table1, Table2;
DROP PROC Proc1;
GO

Here is the result set.

referenced_id, table_name, column_name

------------- ----------- -----------

2139154566 Table1 NULL

2139154566 Table1 a

2139154566 Table1 b

2139154566 Table1 c

2707154552 Table2 NULL

2707154552 Table2 c1

2707154552 Table2 c2

Change History

Updated content
Removed the statement, "Column dependencies are not tracked for CLR table-valued functions," from the Remarks section.
Corrected the data type of the referencing_entity_name parameter.

A. Returning entities that are referenced by a database-level DDL trigger

B. Returning entities that are referenced by an object

C. Returning column dependencies

D. Returning non-schema-bound column dependencies

E. Demonstrating dynamic dependency maintenance

Reference

Other Resources

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