When i am trying to create a repository using repository manager it showing the following message " Database exits but the repository tables are not valid".
That just means that a repository has not yet been created on the user ID you specified. This is just informational if you are creating it for the first time but would be indicative that you are logged in to the wrong account if you are trying to upgrade an existing repository.
Could be that the table owners are different, happens in SQL Server occasionally.
DataServices uses the connect information and then executes a SQL like “select * from AL_VERSION”. There might be such a table but owned by another user e.g. WERNER.AL_VERSION. Now it depends on the settings what the default owner is. If the default is “dbo”, the SQL above will be translated by the database to “select * from dbo.AL_VERSION” and yes, this table does not exist. So either recreate the repo with the default owner or change the default owner.
Actually, above should never happen as you specified the same connect information when creating the repo with repo manager and there we issue the create commands without an owner either, hence the default is used. The same default as for reading. But if the default was changed in the database inbetween…