Monday, March 26, 2012
Why Invalid Object Name 'dbo.__MigrationHistory'?
Unfortunately I am using Entity Framework in my project. After migration support added to Entity Framework I thought using this feature may help me feel a little better about Entity Framework . But the way migration is implemented in EF shows that nothing has changed. Migration has lots of problems and bugs.
After carefully doing all the required cumbersome procedures Entity Framework migration failed to work and I found no workaround until I strangely faced the exception 'Invalid Object Name 'dbo.__MigrationHistory''. This exception give me a clue about the cause of my problems.
It seems that Entity Framework team do not use appropriate testing methods and they only care about the main courses and are very negligent about alternative cases. For example in this case they presumed that always the default schema is dbo. It creates __MigrationHistory on the default schema, but queries for it on the dbo schema.
After a while I find another problem. Entity Framework also tries to insert rows into __MigrationHistory without specifying schema name.
Ok, I wrote this code to make Entity Framework script generator apply 'dbo.' before the __MigrationHistory. I know this is naive solution but at least it works.