What if there is no primary key?
Should you create a database table without a primary key? No. Every table should have some column (or set of columns) that uniquely identifies one and only one row. It’s true, without a primary key (or some unique key), you don’t have an insertion anomaly if you go to insert the same data multiple times.
How can we remove duplicate records from the table which doesn’t have primary key?
So to delete the duplicate record with SQL Server we can use the SET ROWCOUNT command to limit the number of rows affected by a query. By setting it to 1 we can just delete one of these rows in the table. Note: the select commands are just used to show the data prior and after the delete occurs.
How do I delete a database record?
Delete a record
- Open the table in Datasheet View or form in Form View.
- Select the record or records that you want to delete. To select a record, click the record selector next to the record, if the record selector is available.
- Press DELETE, select Home > Records > Delete, or press Ctrl+Minus Sign (-).
Should I always have a primary key?
No. Every table should have some column (or set of columns) that uniquely identifies one and only one row. It makes it much easier to maintain the data. It’s true, without a primary key (or some unique key), you don’t have an insertion anomaly if you go to insert the same data multiple times.
How to delete duplicate records in a table with no primary?
DELETE Duplicate Records Using ROWCOUNT. So to delete the duplicate record with SQL Server we can use the SET ROWCOUNT command to limit the number of rows affected by a query. By setting it to 1 we can just delete one of these rows in the table.
Can a table be created without a primary key?
Every once in awhile a table gets created without a primary key and duplicate records get entered. The problem gets even worse when you have two identical rows in the table and there is no way to distinguish between the two rows. So how do you delete the duplicate record?
How to delete a primary key in SQL Server?
If you don’t want to create a new primary key you can use the TOP command in SQL Server: delete sub from (select ROW_NUMBER () OVer (Partition by empid order by empid)cnt from employee)sub where sub.cnt>1