How to insert values?
I have on table having four columns,
There is no primary Key to table.
There are some records in the table
Now I am inserting new records, but before insertion, I wants to verify If the records with same values is present in table or not? If it is , then insertion will not be done. else record shall be inserted. I m thinking about triggers. When I use insert option, table is get lock & I am not able to use it.
So I request all to guide me.