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As you continue to explore the intricacies of table structures, understanding the role and functionality of constraints becomes essential. Constraints are rules that we apply to data columns in a ...
In mysql, the unique constraint is used to uniquely identify each record in a table.unique constraint on create tablethe following statement creates a unique constraint on the "id" column when the ...
In mysql, the default constraint is used to insert value into a column in a table. if there is no value is specified for a column then the default value will be added to column for all new ...
In MYSQL, some common data types and constraints are INT (an integer number that can be signed or unsigned with a maximum display width in parentheses), VARCHAR ...
Any conlumn in the unique constraint must not have null value, otherwise the update will violate the constraint and cause duplicates. This is considered as a bug #8173 of MySQL with long history, ...