Tag: databases

Quizzes (243) Questions (4862)

Questions Related to databases

Multiple choice technology databases

What is true about PRIMARY KEY? Choose all that apply

  1. Can be defined on a single column or multiple columns in the table.

  2. Can be defined only on a single column in the table.

  3. A UNIQUE index is automatically created once PRIMARY KEY is defined on the table.

  4. A NON-UNIQUE index is automatically created once PRIMARY KEY is defined on the table.

  5. NOT NULL constraint is implicitly enforced on the columns which are part of the PRIMARY KEY

  6. NULL constraint is implicitly enforced on the columns which are part of the PRIMARY KEY
Reveal answer Fill a bubble to check yourself
A,C,E Correct answer
Full explanation
Multiple choice technology databases

What is true about UNIQUE KEY? Choose all that apply

  1. Can be defined only on a single column in the table.

  2. Can be defined on a single column or multiple columns in the table.

  3. A UNIQUE index is automatically created once UNIQUE KEY is defined on the table.

  4. A NON-UNIQUE index is automatically created once UNIQUE KEY is defined on the table.

  5. NULL values are NOT acceptable on the columns, which are part of UNIQUE KEY

  6. NULL values are acceptable, which are part of UNIQUE KEY
Reveal answer Fill a bubble to check yourself
B,C,F Correct answer
Full explanation
Multiple choice technology databases

What is true about CHECK constraint? Choose all that apply

  1. Must evaluate to BOOLEAN expression

  2. Not necessarily evaluates to BOOLEAN expression

  3. Requires that a column (or combination of columns) satisfy a condition for every row in the table excluding nulls.

  4. Columns which, are part of CHECK constraint, may accept NULL values

  5. Columns which, are part of CHECK constraint, can NOT accept NULL values
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Full explanation
Multiple choice technology databases

What is true about FOREIGN KEY constraint? Choose all that apply

  1. Defines relations between the tables

  2. The table that includes the foreign key is called the dependent or child table

  3. The table that includes the foreign key is called the parent table

  4. The table that is referenced by the foreign key is called the parent table

  5. The table that is referenced by the foreign key is called the dependent or child table
Reveal answer Fill a bubble to check yourself
A,B,D Correct answer
Full explanation