DIDACTIC UNIT 3 QUIZ

1.      Among the following schemes, choose which ones are part of the ANSI/SPARC architecture.

• External schema

• Business schema

• UML schema

• Logical schema

• Internal schema

Choose the FALSE statement regarding the conceptual scheme

• Description of an information system regardless of whether or not database techniques are used.

• It describes the information and functions of the organization from a computer point of view.

• Description of an information system from a DBMS-independent organizational point of view.

Data independence is the property that ensures that application programs are independent of…

• … details of the conceptual representation of the data they access.

• … changes made to data they do not use.

• … the changes made to data that even use.

____________ independence: External schemas and application programs must not be affected by modifications to the logical schema on data they do not use. Indicate the missing word.

Select the options that correspond to the objectives of the database techniques.

• Obtain the atomicity of users.

• Obtain the definition of the conceptual scheme.

• Maintaining the quality of information.

• Independence of applications with respect to how data is stored.

Which statement is FALSE regarding transaction definition operations?

• User Commit - Indicates the success of the transaction by storing the changes permanently.

• DBMS Commit. - Indicates the success of the transaction by saving the changes permanently.

• User Rollback. - Indicates that the user does not want to save the changes made.

• DBMS Rollback. - The transaction fails for some reason and the DBMS undoes the operations performed

What properties must a transaction meet in order to be processed correctly?

• Isolation

• Atomicity

• Confirmation

• Persistence

• Quality

The property of the ________ states that the transaction must result in a database state in which all integrity constraints are met. Indicate the missing word.

Choose the FALSE statement about integrity constraint checking.

• The check is performed when the database changes (an update operation is executed).

• The constraints are defined in the logical schema and the DBMS must ensure compliance with them.

• Restrictions that are not included in the database schema are to be maintained in the database management systems.

Choose the correct statement about semantic integrity.

• In the deferred check, the restriction is checked at the end of the transaction.

• In the immediate check the restriction is checked immediately after the completion of the transaction.

• To check a static constraint, two successive states are required.

• Restore actions cannot be specified when a constraint is not met.