what is rdbms ? easy nd full explanation let`s learn it.

   What is RDBMS?

      Rdbms signifies relational database management system.It is used to organise and manipulate the data like –Oracle,DB2,MS SQL server,My SQL etc.

                                            & nbsp;                    Therefore, rdbmses are subset of DBMSes .A relational database refer to a database that keep/store data in a structured format,using rows and columns. By this it easy to find  and retrieve specific values within the database the queries run across multiple tables at once by the rational structure.
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What is DBMS?

     DBMS signify database management system.  DBMS provides user's and programmer's a systematic way/organised to make , update & run data.

    What is table?

      Table is collection of related data entries which means that the table should contain column  and rows. Horizontal subset of the table knew as a row and  the vertical subset of the table knew as a column . 

  The rows in  the relation are not ordered.
   "Since relation is a set aren't ordered hence no ordering defined on tuples of relation".

    Meta data:-

             Data that describe the properties or characters of other data some of there  properties consist data.ex:- datatype - integer,chara char,float,double.

    Key:-

     An group of attributes in a table that identifies a tuple uniquely is known as a key.

Types of key are following:-

          

• Primary key:-

       Candidate key selected identify tuples/records uniquely.

•   Alternate key:--

       Candidate key that aren't select to be primary key . It can be any of keys.

• Foreign key:--

        Attributes or set of attribute within one relation that matches candidate key same relation.

• Secondary key:-

       Attribute or set of attribute used for compunction key accessing records, but not necessarily unique.

• Composite key:-

      If we use multiple attributes to create a primary key than that primary key is called composite key.

•  Candidate key:-

      A minimum set of attributes that uniquely identifies each occurrence of a tuple. Attributes of candidate can`t have null value.

• Advantage:-

     1. Support for acid trans action. 

     2.  Security

     3.  Data manipulation.

     4.  provides multiple interface.

     5.  Good integrity.

•    Disadvantages:-

     1  sharing of data is poor.
     2  inconsistent data.

     3  inflexibility.

     4  inforcement of standards are poor.