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     /   _____/\_____  \ |    |    \_   _____/\______ \
     \_____  \  /  / \  \|    |     |    __)_  |    |  \
     /        \/   \_/.  \    |___  |        \ |    `   \
    /_______  /\_____\ \_/_______ \/_______  //_______  /
            \/        \__>       \/        \/         \/
    
    
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    . |02.03 - SQL, DDL and DML                               .
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      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.
    
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