Επεξεργασία

Κοινή χρήση μέσω

sys.dm_sql_referenced_entities (Transact-SQL)

  • Άρθρο

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance

Returns one row for each user-defined entity that is referenced by name in the definition of the specified referencing entity in SQL Server. 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.

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 when the referenced entity does not exist in the database or when the name resolution is caller dependent. In the latter 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.
is_selected bit 1 = The object or column is selected.
is_updated bit 1 = The object or column is modified.
is_select_all bit 1 = The object is used in a SELECT * clause (object-level only).
is_all_columns_found bit 1 = All column dependencies for the object could be found.

0 = Column dependencies for the object could not be found.
is_insert_all bit 1 = The object is used in an INSERT statement without a column list (object-level only).

This column was added in SQL Server 2016.
is_incomplete bit 1 = The object or column has a binding error and is incomplete.

This column was added in SQL Server 2016 SP2.

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.

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.

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. Return 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 AdventureWorks2022;  
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. Return entities that are referenced by an object

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

USE AdventureWorks2022;  
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. Return 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.

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's 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 3 rows for Table2. Because Table1 does not exist, the column dependencies cannot be resolved and error 2020 is returned. The is_all_columns_found column returns 0 for Table1 indicating that there were columns that could not be discovered.

DROP TABLE IF EXISTS 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,
        is_all_columns_found
    FROM
        sys.dm_sql_referenced_entities ('dbo.Proc1', 'OBJECT');
GO

Here's the result set.

referenced_id table_name   referenced_column_name  is_all_columns_found  
------------- ------------ ----------------------- --------------------  
935674381     Table2       NULL                    1  
935674381     Table2       C1                      1  
935674381     Table2       C2                      1  
NULL          Table1       NULL                    0  

Msg 2020, Level 16, State 1, Line 1
The dependencies reported for entity "dbo.Proc1" might not include
 references to all columns. This is either because the entity
 references an object that does not exist or because of an error
 in one or more statements in the entity.  Before rerunning the
 query, ensure that there are no errors in the entity and that
 all objects referenced by the entity exist.

E. Demonstrating dynamic dependency maintenance

This Example E assumes that Example D has been run. Example E shows that dependencies are maintained dynamically. The example does the following things:

  1. Re-creates Table1, which was dropped in Example D.
  2. Run 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. In addition, the is_all_columns_found column returns a 1 for all objects and columns.

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,
        is_all_columns_found
    FROM
        sys.dm_sql_referenced_entities ('dbo.Proc1', 'OBJECT');
GO  
DROP TABLE Table1, Table2;  
DROP PROC Proc1;  
GO

Here's the result set.

referenced_id table_name   referenced_column_name  is_all_columns_found  
------------- ------------ ----------------------- --------------------  
935674381     Table2       NULL                    1 
935674381     Table2       c1                      1 
935674381     Table2       c2                      1 
967674495     Table1       NULL                    1 
967674495     Table1       a                       1  
967674495     Table1       b                       1  
967674495     Table1       c                       1

F. Returning object or column usage

The following example returns the objects and column dependencies of the stored procedure HumanResources.uspUpdateEmployeePersonalInfo. This procedure updates the columns NationalIDNumber, BirthDate,``MaritalStatus, and Gender of the Employee table based on a specified BusinessEntityID value. Another stored procedure, upsLogError is defined in a TRY...CATCH block to capture any execution errors. The is_selected, is_updated, and is_select_all columns return information about how these objects and columns are used within the referencing object. The table and columns that are modified are indicated by a 1 in the is_updated column. The BusinessEntityID column is only selected and the stored procedure uspLogError is neither selected nor modified.

USE AdventureWorks2022;
GO
SELECT
        referenced_entity_name AS table_name,
        referenced_minor_name  AS column_name,
        is_selected,  is_updated,  is_select_all
    FROM
        sys.dm_sql_referenced_entities(
            'HumanResources.uspUpdateEmployeePersonalInfo',
            'OBJECT')
;

Here's the result set.

table_name    column_name         is_selected is_updated is_select_all  
------------- ------------------- ----------- ---------- -------------  
uspLogError   NULL                0           0          0  
Employee      NULL                0           1          0  
Employee      BusinessEntityID    1           0          0  
Employee      NationalIDNumber    0           1          0  
Employee      BirthDate           0           1          0  
Employee      MaritalStatus       0           1          0  
Employee      Gender              0           1          0

See Also

sys.dm_sql_referencing_entities (Transact-SQL)
sys.sql_expression_dependencies (Transact-SQL)