Database client

The client layer represents the interface between the user and the database. 

MySQL clients include the: 

Administrative interface and utilities

Application interface and utilities

Query interface

This is the front end with which users interact. This component represents three 

kinds of users that interact with the RDBMS:

Administrators

Use the administrative interface and utilities, such as 

mysqladmin

 for creating 

or dropping databases and shutting down the MySQL server; 

isamchk

, 

myisamchk

 for table analysis, optimization, and crash recovery; 

mysqldump

for backing up databases or copying to other server.

Applications

Communicate with the RDBMS through MySQL APIs available for various 

programming languages such as C++, PHP, Java, Perl, etc.

Query users

Interact with the RDBMS through a query interface called 

mysql,

 which allows 

the user to issue SQL statements and view the results returned from the 

server.

Database server

Database server represents the core functionality of the database architecture. 

The following four main components can be found in MySQL:

Query processing

Transaction management 

Recovery management

Storage management

Query processing

The Query Processor receives all the SQL commands from MySQL application 

or on line users, parses the SQL code, executes the code, and sends the user 

the response. 

Requests received from an administrative interface are processed by the 

Data 

Definition Language (DDL) compiler

. The DDLs are compiled for direct 

interaction with the database, and are passed to Execution Engine for execution. 

When a request is submitted from an application, the 

Embedded Data 

Manipulation Language (DML) Precompiler 

extracts the relevant SQL 

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MySQL to DB2 UDB Conversion Guide