DELETE, TRUNCATE and DROP – all three commands get rid of table data. How exactly are they different? When should you use which?
A bird’s eye view of their differences, a table comparing the three.
constraints
How to Validate Email Address in SQL
In applications that take user email id as input, there is a need to check for email id validity. Here is a very easy validation for syntax of an email address, using regular expressions in Oracle SQL.
The basic email address format is username@example.com. The SQL will verify that the email address provided fits into that format. This can be used before data entry, or coded on a table as a check constraint.