Deck 4: Constraints

Question 1

Any constraint can be created at the table or the column level.​

Answer 1

False

Question 2

A CHECK constraint requires that a data value meet a certain condition before the record is added to the database table.​

Answer 2

True

Question 3

A constraint for a composite primary key must be created at the table level.​

Answer 3

True

Question 4

A primary key is usually given the abbreviation _pk in the constraint name if the name is assigned by the user.​

Question 5

The CONSTRAINT keyword is required if the user is going to assign a name to a constraint.​

Question 6

A NOT NULL constraint can only be created at the column level.​

Question 7

The table level approach can be used to create any constraint,except a CHECK constraint.​

Question 8

The MODIFY clause is used with the ALTER TABLE command to add a PRIMARY KEY constraint to an existing table.​

Question 9

A PRIMARY KEY constraint will make certain the column designated as the primary key does not contain a NULL value.​

Question 10

Constraints are rules used to enforce business rules,practices,and policies.​

Question 11

A constraint is always enforced at the table level.​

Question 12

A constraint can only be created as part of the CREATE TABLE command.​

Question 13

Only one PRIMARY KEY constraint can exist for each table.​

Question 14

A constraint name can consist of up to 10 characters.​

Question 15

A FOREIGN KEY constraint can be added to the column of a table to ensure that the referenced data value actually exists in the other table.​

Question 16

A FOREIGN KEY constraint will not allow a row containing a NULL value in the foreign key column to be added to the table.​

Question 17

A foreign key constraint can only be created at the column level.​

Question 18

If a FOREIGN KEY constraint exists,then a record cannot be deleted from the parent table if that row is referenced by an entry in the child table.​

Question 19

Constraints are used to ensure the accuracy and integrity of the data contained in the database.​

Question 20

A UNIQUE constraint is the same as a PRIMARY KEY constraint,except that it will accept NULL values.​

Question 21

The default name for a constraint is SYS Cn where n consists of a number that will make the name unique within the database._________________________​

Question 22

When dropping a constraint,the user is always required to specify the name of the constraint being dropped.​

Question 23

A constraint can be added to a table after the table has been populated with data even if the existing data violates the constraint.​

Question 24

Any type of constraint for a single column can be created at the column level._________________________​

Question 25

A Datatype is a rule used to ensure the accuracy of data stored in a database._________________________​

Question 26

If a data value violates a(n)constraint,the entire row is prevented from being added to the table._________________________​

Question 27

A(n)FOREIGN KEY constraint is used to ensure that referential integrity exists between tables._________________________​

Question 28

In the USER_CONSTRAINTS view,the constraint type for a PRIMARY KEY constraint will be listed as PK.​

Question 29

The ALTER TABLE command can be used to disable a constraint.​

Question 30

A constraint can be renamed using the ALTER TABLE command.​

Question 31

If a(n)FOREIGN KEY constraint has been created for a table,it means the data values in that column must be unique and cannot contain NULL values._________________________​

Question 32

Each column can only be included in one constraint.​

Question 33

A NOT NULL constraint can only be created at the table level._________________________​

Question 34

A(n)constraint can be created during the creation of a database table or added to a table afterwards._________________________​

Question 35

A constraint name can consist of up to 25 characters and numbers._________________________​

Question 36

The SYSDATE can be used as a condition in a CHECK constraint.​

Question 37

The ADD clause of the ALTER TABLE command is used to add a PRIMARY KEY constraint to an existing table._________________________​

Question 38

With the exception of the NOT NULL constraint,constraints can be added to a table using the ADD clause of the ALTER TABLE command.​

Question 39

A NOT NULL constraint is a special FOREIGN KEY constraint.​

Question 40

The ALTER TABLE command with the ENABLE clause can be used to enable a constraint.​

Question 41

When dropping a(n)PRIMARY KEY constraint,the name of the column does not need to be included in the ALTER TABLE command._________________________​

Question 42

The ALTER TABLE command can be used to delete an existing constraint._________________________​

Question 43

If the ON DELETE CASCADE keywords are included when a(n)PRIMARY KEY constraint is created,then if a row is deleted from the parent table,any corresponding records in the child table are also deleted._________________________​

Question 44

Which of the following statements about a PRIMARY KEY is incorrect?​

A) ​It identifies which column(s)uniquely identify each record.
B) ​It can be NULL,as long as the FOREIGN KEY contains a value.
C) ​Each data value must be unique.
D) ​none of the above

Question 45

In the USER_CONSTRAINTS view,the constraint type for a NOT NULL constraint will be listed as N._________________________​

Question 46

How can constraints be added to a table?​

A) ​as part of the CREATE TABLE command
B) ​as part of the ALTER TABLE command
C) ​as part of the PRIMARY KEY command
D) ​both a and b

Question 47

The ALTER TABLE command with the MODIFY clause can be used to disable a constraint._________________________​

Question 48

Which of the following is a valid statement?​

A) ​Constraints are rules used to enforce business rules,practices,and policies.
B) ​Constraints prevent errors by not allowing data to be added to tables if the data violates specific rules.
C) ​Constraints ensure the accuracy and integrity of data.
D) ​all of the above

Question 49

A NOT NULL constraint can only be added to an existing table by using the ADD clause with the ALTER TABLE command._________________________​

Question 50

A(n)NOT NULL constraint is a special CHECK constraint with the condition of IS NOT NULL._________________________​

Question 51

The UNIQUE constraint differs from the PRIMARY KEY constraint in what way?​

A) ​The UNIQUE constraint does not allow NULL values.
B) ​The UNIQUE constraint can be created at either the column level or the table level.
C) ​The UNIQUE constraint allows NULL values.
D) ​The UNIQUE constraint ensures that a specific condition is true before a data value is added to a table.

Question 52

The data warehouse contains information about objects included in the database._________________________​

Question 53

A(n)FOREIGN KEY constraint can only reference a column in the parent table that has been designated as the primary key for that table._________________________​

Question 54

In a "one-to-many" relationship,which constraint is usually added to the "many" table?​

A) ​UNIQUE
B) ​PRIMARY KEY
C) ​FOREIGN KEY
D) ​NOT NULL

Question 55

The FOREIGN KEY constraint is usually placed on the "one" side of a one-to-many relationship._________________________​

Question 56

When a FOREIGN KEY constraint is being created,the REFERENTIAL keyword is used to indicate the table being referenced._________________________​

Question 57

Which of the following are used to enforce business rules?​

A) ​syntax
B) ​functions
C) ​constraints
D) ​enforcers

Question 58

The REFERENCE constraint is used to ensure that a data value meets a specified condition before a record is added to a table._________________________​

Question 59

A(n)UNIQUE constraint will allow NULL values to be stored in the designated column._________________________​

Question 60

Both the table-level and column-level approaches to creating a constraint can be included in the same command._________________________​

Question 61

What is the syntax for the default constraint name provided by the Oracle 12c server?​

A) ​SYS_Cn
B) ​PK_Cn
C) ​ORA_Cn
D) ​DEF_Cn

Question 62

A PRIMARY KEY that consists of more than one column is called a(n)____ key.​

A) ​multiple
B) ​composite
C) ​comprehensive
D) ​coherent

Question 63

Which keywords identify a column that,if it contains a value,it must match data contained in another table?​

A) ​FOREIGN KEY
B) ​PRIMARY KEY
C) ​CHECK
D) ​UNIQUE

Question 64

Only one ____ constraint can exist for each table.​

A) ​PRIMARY KEY
B) ​FOREIGN KEY
C) ​UNIQUE
D) ​CHECK

Question 65

​Which of the following is the standard abbreviation for the constraint FOREIGN KEY?

A) ​fkey
B) ​fk
C) ​fky
D) ​frk

Question 66

Which of the following statements about creating constraints is incorrect?​

A) ​If you do not provide a name for a constraint,the Oracle 12c server will issue an error message.
B) ​There are two approaches for creating constraints: at the column level or the table level.
C) ​One industry convention is to use the format tablename_columnname_constraint type for the constraint name.
D) ​none of the above

Question 67

When a constraint is created at the table level,the constraint definition is provided ____ the column definition list.​

A) ​before
B) ​after
C) ​in the middle of
D) ​between columns in

Question 68

Constraints are always enforced at the ____ level.​

A) ​table
B) ​column
C) ​row
D) ​database

Question 69

Which of the following is not a constraint type in Oracle 12c?​

A) ​CHECK
B) ​UNIQUE
C) ​NOT NULL
D) ​REFERENCE

Question 70

When a constraint is created at the ____ level with the CREATE TABLE command,the constraint definition is simply included as part of the column definition.​

A) ​table
B) ​column
C) ​database
D) ​row

Question 71

Which view will display the names of all the constraints that you own?​

A) ​DISPLAY_CONSTRAINTS
B) ​ALL_CONSTRAINTS
C) ​USER_CONSTRAINTS
D) ​TABLE_CONSTRAINTS

Question 72

Which of the following is the standard abbreviation for the constraint NOT NULL?​

A) ​nn
B) ​nl
C) ​nv
D) ​nnv

Question 73

​Which of the following statements about creating constraints is incorrect?​

A) ​If a constraint applies to more than one column,the constraint must be created at the table level.
B) ​Using the column level approach,the definition of the constraint is included as part of the column definition.
C) ​When you create constraints at the column level,the constraint being created applies to the column specified.
D) ​The NOT NULL constraint can be created at either the column level or the table level.

Question 74

The NOT NULL constraint can only be created at the ____ level.​

A) ​table
B) ​column
C) ​database
D) ​both a and b

Question 75

When used with a FOREIGN KEY,the keyword REFERENCES refers to what?​

A) ​reference integrity
B) ​relational integrity
C) ​referential integrity
D) ​relational constraint

Question 76

If the ____ keyword is included when a constraint is created,a constraint name must be provided by the user.​

A) ​CONST
B) ​CONSTRAIN
C) ​CONSTRAINT
D) ​none of the above

Question 77

If a constraint applies to more than one column,the constraint must be created at the ____ level.​

A) ​column
B) ​table
C) ​row
D) ​database

Question 78

Which of the following types of constraints is used to enforce referential integrity?​

A) ​UNIQUE
B) ​REFERS
C) ​FOREIGN KEY
D) ​CHECK

Question 79

A PRIMARY KEY constraint can be added to an existing table by using the ____ clause of the ALTER TABLE command.​

A) ​MODIFY
B) ​ADD
C) ​CONSTRAINT
D) ​none of the above

Question 80

Which of the following statements about the FOREIGN KEY constraint is incorrect?​

A) ​The constraint exists between two tables,called the parent table and the child table.
B) ​When the constraint exists,by default a record cannot be deleted from the parent table if matching entries exist in the child table.
C) ​The constraint can reference any column in another table,even a column that has not been designated as the primary key for the referenced table.
D) ​When the keywords ON DELETE CASCADE are included in the constraint definition,a corresponding child record will automatically be deleted when the parent record is deleted.