Explain the available database integrity constraints.

1.	Explain the available database integrity constraints.
Answer» 1. NOT NULL: it species that a column can never have null values, i.e., not empty 2. UNIQUE: it ensures that no two rows have same value in the specied column. 3. PRIMARY KEY: it declares a column or a set of columns as the primary key of the table. This constraint makes a column NOT NULL and UNIQUE. 4. DEFAULT: it sets a default value for a column when the user does not enter a value for that column. 5. Auto_increment: This constraint is used to perform auto increment the values in a column. That automatically generates serial numbers. Only one auto-increment column per table is allowed.

Answer»

1. NOT NULL: it species that a column can never have null values, i.e., not empty

2. UNIQUE: it ensures that no two rows have same value in the specied column.

3. PRIMARY KEY: it declares a column or a set of columns as the primary key of the table. This constraint makes a column NOT NULL and UNIQUE.

4. DEFAULT: it sets a default value for a column when the user does not enter a value for that column.

5. Auto_increment: This constraint is used to perform auto increment the values in a column. That automatically generates serial numbers. Only one auto-increment column per table is allowed.

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