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The syntax of the ALTER statement is as follows:

ALTER <specification> [Specification name]

The syntax of the DROP TABLE statement is as follows

DROP TABLE "table_name"

These steps will not require to shut down the server and will put the table in a consistent state.

Dump the table through mysqldump. Drop the table. Recreate the table through dump.

Inside-out approach

It begins with the identification of only a few important concepts and, based on these, the design proceeds, spreading outward 'radially'.

It is stated in the question that the database should contain salary history information

This means that the salary of an employee can be incremented more than once. a one-to-many relationship exists.

In a top-down approach

a schema is created through a series of successive refinements, starting from the first schema, which is gradually expanded by using appropriate modifications that increase the detail of the various concepts.

The ALTER statement

changes the properties of an object inside DBMS.

A composite key

in the context of relational databases, is a combination of two or more columns in a table that can be used to uniquely identify each row in the table. Uniqueness is only guaranteed when the columns are combined; when taken individually the columns do not guarantee uniqueness

Mysqldump

is a part of the mysql relational database package that allows you to "dump" a database, or a collection of databases, for backup or transferral to another SQL server.

A Domain

is a set of allowable values for one or more attributes. It is also known as the data domain which refers to all the unique values which a data element may contain.

The UPDATE statement

is used to directly change or modify the values stored in one or more fields in a specified record in a single table.

The CREATE statement

is used to make a new database, table, index, or stored query

The DROP statement

is used to remove an object from an RDBMS

The common concept is that the table's contents

may be restored from the dump

dump tables

means provide a export of the table, including its definition and insert statements, as a script that can be executed to recreate the table from scratch.

The binary logs

store updates that have been made after the backup was made.

In a mixed approach

the designer decomposes the requirements into a number of component

cardinality

the number of rows (or tuples)

In a bottom-up approach

the preliminary specifications are broken down into smaller components so that each component describes a basic fragment of the specifications.

To create a one-to-many relationship between salary and employee

you have to create a separate entity for salary, and create a foreign key referring to the primary key of the Employees table.