SQL That string looks perfectly acceptable to me, because I understand the variations in date formats and that looks like a UK representation of "27th April 2013" to me, but the database doesn't know that.
To remedy this, we must either explicitly use the types in more detail.
Later, almost all programming languages adopted this theory and introduced the regular expression concepts in them.
By practicing simple data validation rules, databases are more consistent, functional, and provide more value to their users.
When using SQL, data validation is the aspect of a database that keeps data consistent but is very stupid to use. The key factors in data integrity are constraints, referential integrity and the delete and update options.
Data validation is often a topic of great importance when it comes to databases.
Since information is constantly being updated, deleted, queried, or moved around, having valid data is a must.