1.4 Tables

Question 1

Characteristics of a table

Answer 1

A table has a name, a fixed sequence of columns, and a varying set of rows.

Question 2

What is a column?

Answer 2

A column, also known as an attribute or field, represents a single category of data within a table. Each column contains values of a specific type (e.g., text, numbers, dates) and describes a particular characteristic of the data stored in each row.

Question 3

What is a row?

Answer 3

A row is an unnamed sequence of values. Each value corresponds to a column and belongs to the column’s data type. Also known as a record or tuple, represents a single, specific entry within a table in a database.

Question 4

What is a cell?

Answer 4

single column of a single row.

Question 5

What is an empty table?

Answer 5

A table without rows

Question 6

What is data independence?

Answer 6

Data independence is a fundamental concept in database management that refers to the separation of data structure from the applications that use the data. This allows changes to be made to the data’s storage or organization without impacting the applications that rely on it.

Question 7

CREATE TABLE

Answer 7

Creates a new table by specifying the table name, column names, and column data types.

CREATE TABLE Employees (
EmployeeID INT PRIMARY KEY,
FirstName VARCHAR(50),
LastName VARCHAR(50),
DateOfBirth DATE,
Position VARCHAR(100),
Salary DECIMAL(10, 2)
);

Question 8

DROP TABLE

Answer 8

Deletes a table, along with all the table’s rows, from a database.

DROP TABLE Employees;

Question 9

ALTER TABLE

Answer 9

The ALTER TABLE statement adds, deletes, or modifies columns on an existing table.

Question 10

Rename a column

Answer 10

ALTER TABLE table_name
RENAME COLUMN old_column_name TO new_column_name;

Question 11

Modify a column’s datatype

Answer 11

ALTER TABLE table_name
MODIFY COLUMN column_name new_data_type;

Question 12

Delete a column

Answer 12

ALTER TABLE table_name
DROP COLUMN column_name;