Dropping a table with all its dependencies (Microsoft SQL Server) - sql

Question

How can I drop a table with all its dependencies [SPs, Views, etc.] (Microsoft SQL Server) without knowing its dependencies upfront? I know I can display all dependencies in Mangement Studio but I'm searching for utility script that I could simply speficy an object and it would drop this object with all its dependencies.

Answer 1

The best thing to do it is "Generate scripts for Drop"
Select Database -> Right Click -> Tasks -> Generate Scripts - will open wizard for generating scripts
Select the database -> next
Set option 'Script to create' to true (want to create)
Set option 'Script to Drop' to true (want to drop)
Set option 'Generate script for dependent object' to true -> Next
Select the Check box to select objects wish to create script
Select the choice to write script (File, New window, Clipboard)
Execute the script
This way we can customize our script i.e., we can do scripting for selected objects of a database.
I hope this will help you!
Best Wishes, JP

Answer 2

You can use Sp_Depends to find the dependencies. With that you can modify the script from this answer Maybe someone less lazy than me will do that for you.
Note: Each object of course could have its own dependencies so you'll need to process them as well.

Answer 3

Delete a SQL object using its schema-qualified name. For tables, the constraints are dropped first.
Errors are ignored.
create procedure [dbo].[spDropObject] (#fullname nvarchar(520))
as
begin
begin try
declare #type nvarchar(5)
declare #resolvedFullname nvarchar(520)
declare #resolvedName nvarchar(255)
set #type = null
set #resolvedFullname = null
set #resolvedName = null
--find the object
select
#type = o.[type]
,#resolvedFullname = '[' + object_schema_name(o.id) + '].[' + o.[name] + ']'
,#resolvedName = '[' + o.[name] + ']'
from dbo.sysobjects o
where id = object_id(#fullname)
--PROCEDURE
if(#type = 'P')
begin
exec('drop procedure ' + #resolvedFullname);
return;
end
--VIEW
if(#type = 'V')
begin
exec('drop view ' + #resolvedFullname);
return;
end
--FUNCTION
if(#type = 'FN' or #type = 'TF')
begin
exec('drop function ' + #resolvedFullname);
return;
end
--TRIGGER
if(#type = 'TF')
begin
exec('drop trigger ' + #resolvedFullname);
return;
end
--CONSTRAINT
if(#type = 'C' or #type = 'UQ' or #type = 'D' or #type = 'F' or #type = 'PK' or #type = 'K')
begin
declare #fullTablename nvarchar(520);
set #fullTablename = null
--find the contraint's table
select #fullTablename ='[' + object_schema_name(t.[object_id]) + '].[' + t.[Name] + ']'
from sys.tables t
join sys.schemas s on t.schema_id = s.schema_id
where t.object_id = (select parent_obj from dbo.sysobjects where id = object_id(#resolvedFullname))
exec('alter table ' + #fullTablename + ' drop constraint ' + #resolvedName);
return;
end
--TABLE (drop all constraints then drop the table)
if(#type = 'U')
begin
--find FK references to the table
declare #fktab table([Name] nvarchar(255))
insert #fktab
select
[Name] = '[' + object_name(fkc.[constraint_object_id]) + ']'
/*
,[Parent] = '[' + object_schema_name(fkc.[parent_object_id]) + '].[' + object_name(fkc.[parent_object_id]) + ']'
,[Ref] = '[' + object_schema_name(fkc.[referenced_object_id]) + '].[' + object_name(fkc.[referenced_object_id]) + ']'
*/
from sys.foreign_key_columns as fkc
where referenced_object_id = object_id(#resolvedFullname)
order by [Name]
--iterate FKs
while(1=1)
begin
declare #constraint nvarchar(255)
set #constraint = null
select top 1
#constraint = [Name]
from #fktab
if(#constraint is not null)
begin
--drop FK constraint
exec [dbo].[spDropObject] #constraint;
delete from #fktab where [Name] = #constraint --remove current record from working table
end
else break;
end
--find constraints for table
declare #constraintTab table ([Name] nvarchar(255));
insert #constraintTab
select [name]
from sys.objects
where parent_object_id = object_id(#resolvedFullname)
order by [name]
--iterate constraints
while(1=1)
begin
set #constraint = null;
select top 1 #constraint = [Name] from #constraintTab
if(#constraint is not null)
begin
--drop constraint
exec [dbo].[spDropObject] #constraint;
delete from #constraintTab where [Name] = #constraint --remove current record from working table
end
else break;
end
--drop table
exec('drop table ' + #resolvedFullname);
return;
end
end try
begin catch
declare #message nvarchar(max)
set #message = error_message( ) ;
print #message
end catch
end

Answer 4

In my case, I specifically wanted to drop a specified table and the tables that depend on that table. It wasn't useful to me to only drop the foreign key constraints that reference it. I wrote a stored procedure to do this
CREATE PROCEDURE DropDependentTables (
#tableName NVARCHAR(64))
AS
-- Find and drop all tables that depend on #tableName
WHILE EXISTS(SELECT *
FROM sys.foreign_keys
WHERE OBJECT_NAME(referenced_object_id) = #tableName AND
OBJECT_NAME(parent_object_id) != #tableName)
BEGIN
DECLARE #dependentTableName NVARCHAR(64)
SELECT TOP 1 #dependentTableName = OBJECT_NAME(parent_object_id)
FROM sys.foreign_keys
WHERE OBJECT_NAME(referenced_object_id) = #tableName AND
OBJECT_NAME(parent_object_id) != #tableName
EXEC DropDependentTables #dependentTableName
END

Answer 5

I'm going to leave a late answer (after around 10 years). I hope you'll find it handy.
In our company, we use this script to properly delete database tables. For each table, we first drop the dependencies (REFERENTIAL_CONSTRAINTS) then delete the table itself.
USE [database-name]
DECLARE #Sql NVARCHAR(500) DECLARE #Cursor CURSOR
SET #Cursor = CURSOR FAST_FORWARD FOR
SELECT DISTINCT sql = 'ALTER TABLE [' + tc2.TABLE_SCHEMA + '].[' + tc2.TABLE_NAME + '] DROP [' + rc1.CONSTRAINT_NAME + '];'
FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc1
LEFT JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc2 ON tc2.CONSTRAINT_NAME =rc1.CONSTRAINT_NAME
OPEN #Cursor FETCH NEXT FROM #Cursor INTO #Sql
WHILE (##FETCH_STATUS = 0)
BEGIN
Exec sp_executesql #Sql
FETCH NEXT FROM #Cursor INTO #Sql
END
CLOSE #Cursor DEALLOCATE #Cursor
GO
EXEC sp_MSforeachtable 'DROP TABLE ?'
GO
The credit goes to a colleague of mine, Abolfazl Najafzade, for the script.