Category Archives: sql

SQL – Check Constraint Table of content The SQL CHECK Constraint The SQL CHECK constraint is used to add conditions on a column of a table. Once you add the check constraint on a column, it ensures that the data entered into the column meets the specified conditions. If a particular record does not meet […]

SQL – Default Constraint Table of content The SQL DEFAULT Constraint The SQL DEFAULT Constraint is used to specify the default value for a column of a table. We usually set default value while creating the table. The default values are treated as the column values if no values are provided while inserting the data, […]

SQL – NULL Values Table of content SQL uses the term NULL to represent a non-existent data value in the database. These values are not the same as an empty string or a zero. They don”t hold any space in the database and are used to signify the absence of a value or the unknown […]