BasesDatos DAW T2 Relational Databases

Which of the following fields could be a primary key?. Address. Name. Phone. NIF.

The Data Definition Language describes data structures and integrity constraints. True or false?. True. False.

A primary key: Can contain null values. Is an alternative key. Can be repeated. Is a superkey.

What does the following SQL statement do? GRANT CONNECT TO Sonia;. Grants Sonia the Connect role with all associated privileges. Prevents Sonia from accessing the database. Denies Sonia the Connect role and all associated privileges. Removes Sonia from the connection.

Keys that are attributes or sets of attributes in a relation whose values coincide with the values of the primary key of another relation (or the same one) are called: Primary. Secondary. Foreign. External.

The REVOKE statement is used to: Modify permissions. Create database objects. Revoke permissions. Grant permissions.

Constraints for non-repeated values are made with: ADD CONSTRAINT CHECK.... ADD CONSTRAINT FOREIGN KEY.... ADD CONSTRAINT PRIMARY KEY.... ADD CONSTRAINT UNIQUE....

When creating a table, all fields of the table must be created. True or false?. True. False.

To add a constraint to an already created table, the statement is: ALTER TABLE TableName ALTER CONSTRAINT. ALTER TABLE TableName ADD COLUMN. ALTER TABLE TableName ADD CONSTRAINT.... CREATE CONSTRAINT ConstraintName TO TableName.

What does the following SQL statement do? RENAME NombreViejo TO NombreNuevo;. Changes the name of a table. Changes the name of a user. Changes the name of a constraint. Changes the name of a field.