SQL Constraint 2

Which constraint is used to enforce a relationship between two tables ?

foreign key

primary key

Unique key

Check

Non of above

Unique key constraints define a column or series of columns that uniquely identify a given row in a table.

true

false

Which of the following constraint allows null value ?

primary key

Unique Key

Not Null

All of above

Which of the following constraints are integrity constraints ?

Primary Key

Unique Key

Foreign Key

Check

Which of the above is correct to create composite primary key order_id and item_no in Product table ?

CREATE TABLE Product(
order_id NUMBER,
item_no NUMBER,
productId NUMBER,
PRIMARY KEY (order_id, item_no));

CREATE TABLE Product(
order_id NUMBER,
item_no NUMBER,
productId NUMBER,
COMPOSITE PRIMARY KEY (order_id, item_no));

CREATE TABLE Product(
order_id NUMBER,
item_no NUMBER,
productId NUMBER,
COMPOSITE KEY (order_id, item_no));

All the above

Which of the following is corect format to create primary key ?

CREATE TABLE Table1 (id NUMBER PRIMARY KEY, C1 VARCHAR2(30));

CREATE TABLE Table1(id NUMBER PRIMARY KEY, C1 VARCHAR2(30) ,PRIMARY KEY (id))

CREATE TABLE Table1(id NUMBER PRIMARY KEY, C1 VARCHAR2(30) , CONSTRAINT t1_pk PRIMARY KEY (id));

All the above

Which of the following are not true about Foreign Key ?

Foreign key is a column in a table that does NOT uniquely identify rows in that table

Foreign key is a column in a table that does uniquely identify rows in that table

It is used as a link to matching columns in other tables to indicate a relationship.

It can be null

Which of the option is used ,If rows are deleted from the parent table, referenced rows field will automatically be set to null in the child table.

ON DELETE CASCADE

ON DELETE SET NULL

ON UPDATE CASCADE

SET NULL

How to use 'Check' constraint to create table and ensure no employee is paid less 20000 and greater than 4000 ?

CREATE TABLE emp (empno NUMBER PRIMARY KEY,
ename VARCHAR2(20),
sal NUMBER(10,2) CHECK (sal between 4000 and 20000)
);

CREATE TABLE emp (empno NUMBER PRIMARY KEY,
ename VARCHAR2(20),
sal NUMBER(10,2) and CHECK (sal between 1000 and 20000)
);

CREATE TABLE emp (empno NUMBER PRIMARY KEY,
ename VARCHAR2(20),
sal NUMBER(10,2), CHECK (sal between 1000 and 20000)
);

CREATE TABLE emp (empno NUMBER PRIMARY KEY,
ename VARCHAR2(20),
sal NUMBER(10,2) CHECK (sal in between 1000 and 20000)
);

How to enable all the referenced foreign keys and the primary or unique key ?

ALTER TABLE table_name CONSTRAIN constraint_name ENABLE;

ALTER TABLE table_name ENABLE CONSTRAINT constraint_name;

ALTER TABLE table_name MODIFY CONSTRAINT constraint_name ENABLE ;

ALTER TABLE table_name RENAME CONSTRAINT constraint_name ENABLE ;