Before any changes to database structure are attempted one should first: All of these test any changes on a test database only. create a complete backup of the operational database only. clearly understand the current structure and contents of the database only. TRUE ANSWER : ? YOUR ANSWER : ?
Dependency graphs are diagrams that consist of nodes and arcs that show the dependencies of a database. False True TRUE ANSWER : ? YOUR ANSWER : ?
Database redesign is especially difficult if the database has no data. False True TRUE ANSWER : ? YOUR ANSWER : ?
The SQL-92 command to change a table name is RENAME TABLE. True False TRUE ANSWER : ? YOUR ANSWER : ?
What SQL command will allow you to change the table STUDENT to add the constraint named GradeCheck that states that the values of the Grade column must be greater than 0? None of these ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0); ALTER TABLE STUDENT ALTER CONSTRAINT GradeCheck (Grade > 0); ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck (Grade > 0); TRUE ANSWER : ? YOUR ANSWER : ?
Reverse engineering is the process of reading a database schema and producing a data model from that schema. False True TRUE ANSWER : ? YOUR ANSWER : ?
The NOT EXISTS keyword will be true if: both of these two conditions are met. neither of these two conditions is met. any row in the subquery meets the condition. all rows in the subquery fail the condition. TRUE ANSWER : ? YOUR ANSWER : ?
Typically, there should be at least two different copies of the database schema used in the redesign process. False True TRUE ANSWER : ? YOUR ANSWER : ?
The NOT EXISTS keyword will be true if any row in the subquery meets the condition. False True TRUE ANSWER : ? YOUR ANSWER : ?
The data model produced from the reverse engineering process is a true logical model. False True TRUE ANSWER : ? YOUR ANSWER : ?