|=--------------------------------------------------=| _________________ .____ ___________________ / _____/\_____ \ | | \_ _____/\______ \ \_____ \ / / \ \| | | __)_ | | \ / \/ \_/. \ |___ | \ | ` \ /_______ /\_____\ \_/_______ \/_______ //_______ / \/ \__> \/ \/ \/ |=--------------------------------------------------=| . |02.03 - SQL, DDL and DML . |=--------------------------------------------------=| The Database Management System (DBMS) is using the data model when it works with data. There are two main groups of languages for data manipulation. The first are procedural languages. When the programmer is using procedural programming language for data manipulation the description of data has to be defined. Then for further work the algorithms on how to use these data has to be specified. On the other hand when the non-procedural language is used there is no need to specify the description of the data. Query languages are in the group of the non-procedural languages. When using Query language the description of the data structure is already in the database data dictionary. The basic of the query language command is one sentence or query. The main purpose to enter queries to the database system is the manipulation of the database inner structure. The Query language has two main distinction for the queries by it's usage. The first subset of queries is for the data definition (Data Definition Language Statements or DDL). The second subset of queries is used for data manipulation (Data Manipulation Language Statements or DML). During the time there were many proposals for query languages. But the main industry standard is the Structured Query Language (SQL). It is implemented in the most of the database products. |=--------------------------------------------------=| ; v | Thanks Linux and Vim | buy me a coffee | o |; |=--------------------------------------------------=| |