Assertion. The foreign-keys of tables are used to establish relationships with other tables and must be handled carefully.

Reason. Referential integrity is a system of rules that a DBMS uses to ensure that the relationships between tables remain valid and no accidental change or deletion occurs in the related data.

Assertion. A unique value that identifies each row uniquely is the primary key.

Reason. Only one column can be made the primary key.

Assertion. There is a difference between a field being empty or storing NULL value in a field.

Reason. The NULL value is a legal way of signifying that no value exists in the field.

Assertion. The ALL and DISTINCT clauses of a SELECT query are related.

Reason. The ALL clause is the opposite of the DISTINCT clause of a SELECT Query.

Assertion. The WHERE and HAVING clauses are used for the same thing in a SELECT query.

Reason. Both WHERE and HAVING clauses are used to specify conditions at different levels.

Assertion. Both WHERE and HAVING clauses are used to specify conditions.

Reason. The WHERE and HAVING clauses are interchangeable.

Assertion. DDL and DML are not the same.

Reason. DDL and DML are two subcategories of SQL where DDL creates the objects and DML manipulates the data.

Assertion. DDL and DML both are part of SQL.

Reason. Both DDL and DML are interchangeable.

Assertion. Both BETWEEN and IN operators can choose from a list of values.

Reason. The value ranges and a list of values are interpreted in the same way in SQL.

Assertion. The PRIMARY KEY and UNIQUE constraints are the same.

Reason. The columns with PRIMARY KEY or UNIQUE constraints have unique values for each row.