Oracle Constraints By Blue Blaze
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- 1.WHERE clauses allows alias names.
- A.
True
- B.
False
- 2._________ constraint is used to limit the value range that can be placed in a column.
- 3.Select the statement which is collectively known as TCL?
- A.
Commit
- B.
Savepoint
- C.
Rollback
- D.
Grant
- 4.Constraints are classified into _________ and __________ constraints.
- A.
Column level
- B.
Table level
- C.
Row level
- 5.You can drop a column in a table with a simple ALTER TABLE DROP COLUMN statement, even if the column is referenced in a constraint.
- A.
True
- B.
False
- 6.All of a user's constraints can be viewed in the Oracle Data Dictionary view called:
- A.
USER_TABLES
- B.
USER_CONSTRAINTS (*)
- C.
CONSTRAINTS
- D.
TABLE_CONSTRAINTS
- 7.What mechamisn does Oracle use in the background to enforce uniqueness in Primary and Unique key constraints?
- A.
Unique indexes are created in the background by Oracle when Primary and Unique constraints are created or enabled (*)
- B.
Nothing extra is created when Primary Keys and Unique Keys are created
- C.
Internal Pointers
- D.
Ordered Lists
- 8.The command to 'switch off' a constraint is:
- A.
ALTER TABLE STOP CHECKING
- B.
ALTER TABLE DISABLE CONSTRAINT (*)
- C.
ALTER TABLE STOP CONSTRAINTS
- D.
ALTER TABLE PAUSE CONSTRAINT
- 9.Once constraints have been created on a table you will have to live with them as they are unless you drop and re-create the table.
- A.
True
- B.
False
- 10.The SQL WHERE clause:
- A.
limits the column data that are returned.
- B.
Limits the row data are returned.
- C.
Both A and B are correct.
- D.
Neither A nor B are correct.
- 11.Which of the following is valid SQL for an Index?
- A.
CREATE INDEX ID;
- B.
CHANGE INDEX ID;
- C.
ADD INDEX ID;
- D.
REMOVE INDEX ID;
- 12.To remove duplicate rows from the results of an SQL SELECT statement, the ________ qualifier specified must be included.
- A.
ONLY
- B.
UNIQUE
- C.
DISTINCT
- D.
NULL
- 13.There is a possibility to create more than one primary key on a single table
- A.
True
- B.
False
- 14.Check constraint can be used for self refential integrity
- A.
True
- B.
False
- 15.Syntax for Referential integrity?
- A.
Foreign key(field_name)references table_name(field_name)
- B.
Foreign key(field_name)references(field_name) on delete cascade
- C.
Foreign key(field_name)references table_name(field_name) on delete cascade
- D.
Foreign key(field_name)references table_name(field_name) ondelete cascade
- 16.An automatic COMMIT occurs when:
- A.
DDL statement is issued
- B.
DCL statement is issued
- C.
Normal exit from SQL*PLUS without issuing explicit COMMIT or ROLLBACK
- D.
None of the above
- 17.Zero is equivalent to null?
- A.
True
- B.
False
- 18.When two users access the same table's specific row simultaneously , it is possible to update the data before one commits
- A.
True
- B.
False
- 19.Which statement cannot be rolled back and committed automatically
- A.
DDL
- B.
DML
- C.
TCL
- D.
NONE OF THE ABOVE
- 20.Which are the types of locks?
- A.
Automatic
- B.
Manual
- C.
Automatic and manual
- D.
None of the above
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