I have some SQL code that needs to be executed if a certain View exists in a database. How would I go about checking if the View exists?
EDIT: The DBMS being used is Mic
if it's Oracle you would use the "all_views" table.
It really depends on your dbms.
To expand on Kevin's answer.
private bool CustomViewExists(string viewName)
{
using (SalesPad.Data.DataConnection dc = yourconnection)
{
System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand(String.Format(@"IF EXISTS(select * FROM sys.views where name = '{0}')
Select 1
else
Select 0", viewName));
cmd.CommandType = CommandType.Text;
return Convert.ToBoolean(dc.ExecuteScalar(cmd));
}
}
If you want to check the validity and consistency of all the existing views you can use the following query
declare @viewName sysname
declare @cmd sysname
DECLARE check_cursor CURSOR FOR
SELECT cast('['+SCHEMA_NAME(schema_id)+'].['+name+']' as sysname) AS viewname
FROM sys.views
OPEN check_cursor
FETCH NEXT FROM check_cursor
INTO @viewName
WHILE @@FETCH_STATUS = 0
BEGIN
set @cmd='select * from '+@viewName
begin try
exec (@cmd)
end try
begin catch
print 'Error: The view '+@viewName+' is corrupted .'
end catch
FETCH NEXT FROM check_cursor
INTO @viewName
END
CLOSE check_cursor;
DEALLOCATE check_cursor;
FOR SQL SERVER
IF EXISTS(select * FROM sys.views where name = '')
There are already many ways specified above but one of my favourite is missing..
GO
IF OBJECT_ID('nView', 'V') IS NOT NULL
DROP VIEW nView;
GO
WHERE nView
is the name of view
UPDATE 2017-03-25: as @hanesjw suggested to drop a Store Procedure use P
instead of V
as the second argument of OBJECT_ID
GO
IF OBJECT_ID( 'nProcedure', 'P' ) IS NOT NULL
DROP PROCEDURE dbo.sprocName;
GO
For people checking the existence to drop View
use this
From SQL Server 2016 CTP3
you can use new DIE statements instead of big IF
wrappers
syntax
DROP VIEW [ IF EXISTS ] [ schema_name . ] view_name [ ...,n ] [ ; ]
Query :
DROP VIEW IF EXISTS view_name
More info here