constraints

Question 1

Restricts NULL value from being inserted into a column

Answer 1

NOT NULL

Question 2

Verifies that all values in a field satisfy a condition

Answer 2

CHECK

Question 3

Automatically assigns a default value if no value has been specified for the field

Answer 3

DEFAULT

Question 4

Ensures unique values to be inserted into the field

Answer 4

UNIQUE

Question 5

Indexes a field providing faster retrieval of records

Answer 5

INDEX

Question 6

Uniquely identifies each record in a table

Answer 6

PRIMARY KEY

Question 7

Ensures referential integrity for a record in another table

Answer 7

FOREIGN KEY

Question 8

Create table with multiple fields as primary ke

Answer 8

CREATE TABLE Students ( 	 
    ID INT NOT NULL
    LastName VARCHAR(255)
    FirstName VARCHAR(255) NOT NULL,
    CONSTRAINT PK_Student
    PRIMARY KEY (ID, FirstName)
);

Question 9

Set multiple columns as primary key

Answer 9

ALTER TABLE Students
ADD CONSTRAINT PK_Student
PRIMARY KEY (ID, FirstName);

Question 10

Set a column as primary key

Answer 10

ALTER TABLE Students

ADD PRIMARY KEY (ID);

Question 11

Create table with multiple fields as unique

Answer 11

CREATE TABLE Students ( 	 
    ID INT NOT NULL
    LastName VARCHAR(255)
    FirstName VARCHAR(255) NOT NULL
    CONSTRAINT PK_Student
    UNIQUE (ID, FirstName)
);

Question 12

Create index

Answer 12

CREATE INDEX index_name 	 
ON table_name (column_1, column_2);

Question 13

What is Data Integrity?

Answer 13

Data Integrity is the assurance of accuracy and consistency of data over its entire life-cycle, and is a critical aspect to the design, implementation and usage of any system which stores, processes, or retrieves data. It also defines integrity constraints to enforce business rules on the data when it is entered into an application or a database.