Getting SQL Server Cross database Dependencies

Question

SQL Server Version - 2008 R2

I am working on evaluating a DMS solution, with an objective of taking over maintenance. The original solution has one central database, that has data pertaining to the manufacturer. It also has one database for each dealer, which means there are a lot of cross database dependencies.

The problems:

• No DB documentation
• No code comments
• Lots of heaps
• No standard object naming conventions
• The central DB has 460+ tables and 900+ SProcs, in addition to other objects
• Each dealer DB has 370+ tables and 2350+ SProcs, in addition to other objects

As a first step, I am recommending a complete clean-up of the DB, for which it is critical to understand object dependencies, including cross database dependencies. I tried using Red Gate's solution, but the output is way too voluminous. All I want is a list of objects in the databases that do not have any dependencies - they neither depend on other objects, nor are there any objects that depend on them.

Here is the script I have used to get a list of dependencies:

SELECT
DB_NAME() referencing_database_name,
OBJECT_NAME (referencing_id) referencing_entity_name,
ISNULL(referenced_schema_name,'dbo') referenced_schema_name,
referenced_entity_name,
ao.type_desc referenced_entity_type,
ISNULL(referenced_database_name,DB_NAME()) referenced_database_name
FROM sys.sql_expression_dependencies sed
JOIN sys.all_objects ao
ON sed.referenced_entity_name = ao.name 

I will be creating a table - Dependencies - into which I will be inserting this result set from each DB. As a next step, I will also be creating another table - AllObjects- which will contain a list of all objects in the Databases. Here is the script to do this:

SELECT
DB_NAME() DBName,
name,
type_desc
FROM sys.all_objects
WHERE type_desc IN
(
'VIEW',
'SQL_TABLE_VALUED_FUNCTION',
'SQL_STORED_PROCEDURE',
'SQL_INLINE_TABLE_VALUED_FUNCTION',
'USER_TABLE',
'SQL_SCALAR_FUNCTION'
)

Now, a list of name from this table, that do not appear in the referenced_entity_name column in the dependencies table should give a list of objects that I am looking for.

SELECT
AO.DBName,
AO.name,
AO.type_desc
FROM AllObjects AO
LEFT OUTER JOIN Dependencies D ON
D.referenced_database_name = AO.DBName AND
D.referenced_entity_name = AO.name AND
D.referenced_entity_type = AO.type_desc
WHERE 
D.referenced_database_name IS NULL AND
D.referenced_entity_name IS NULL AND
D.referenced_entity_type IS NULL

Now the questions:

1. Some object dependencies seem to be missing in the output. What am I missing?
2. How do I validate that my findings are correct?
3. I mean is there a different way to do this, so I can compare the results and double check?

Thanks in advance,

Raj

Answer 1

You can compare your results to the ones that the following script finds. Here is the full article

CREATE PROCEDURE [dbo].[get_crossdatabase_dependencies] AS

SET NOCOUNT ON;

CREATE TABLE #databases(
    database_id int, 
    database_name sysname
);

INSERT INTO #databases(database_id, database_name)
SELECT database_id, [name]
FROM sys.databases
WHERE 1 = 1
    AND [state] <> 6 /* ignore offline DBs */
    AND database_id > 4; /* ignore system DBs */

DECLARE 
    @database_id int, 
    @database_name sysname, 
    @sql varchar(max);

CREATE TABLE #dependencies(
    referencing_database varchar(max),
    referencing_schema varchar(max),
    referencing_object_name varchar(max),
    referenced_server varchar(max),
    referenced_database varchar(max),
    referenced_schema varchar(max),
    referenced_object_name varchar(max)
);

WHILE (SELECT COUNT(*) FROM #databases) > 0 BEGIN
    SELECT TOP 1 @database_id = database_id, 
                 @database_name = database_name 
    FROM #databases;

    SET @sql = 'INSERT INTO #dependencies select 
        DB_NAME(' + convert(varchar,@database_id) + '), 
        OBJECT_SCHEMA_NAME(referencing_id,' 
            + convert(varchar,@database_id) +'), 
        OBJECT_NAME(referencing_id,' + convert(varchar,@database_id) + '), 
        referenced_server_name,
        ISNULL(referenced_database_name, db_name(' 
             + convert(varchar,@database_id) + ')),
        referenced_schema_name,
        referenced_entity_name
    FROM ' + quotename(@database_name) + '.sys.sql_expression_dependencies';

    EXEC(@sql);

    DELETE FROM #databases WHERE database_id = @database_id;
END;

SET NOCOUNT OFF;

SELECT * FROM #dependencies;