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Key Field

        In the   ase   data between tables can be related on the basis of a common field called key field.  he key field
        links the data between two or more tables.   ase  sets relationship by comparing the key fields of tables and
        if they match  there is an automatic linking which is known as    O- OIN.  sers can specifically link any two
        tables on the basis of key fields by creating a relationship.

        Primary Key

         rimary  key  is  a  field  which  is  used  to  uni uely  identify  records  in  a  database.  It  is  a  uni ue  field  and  it
        cannot be left blank. There can be only one primary key in a table. If there are more than one primary
        keys  then there will be two identities against a row.  here can be only one identity against a row. So  we cannot
        have more than one primary key. To make retrieval of records faster, Primary keys are indexed in database.

        For example  in a bank s master file  the account is identified by one account number. Students  dmission
        number   ccount number   ustomer number and  eceipt number are the examples for primary key fields.

        Composite Key

        Composite key is also called as composite primary key. It refers to combination of two or more fields that can
        uni uely identify or retrieve records. For example  the  oll No and the  ro ect fields in a student table can be
        used as a Composite key to uniquely identify each record in the table.

        Foreign Key

         he main table of a database is referred to as the  Master  able  and the tables in which the related data is
        stored are referred to as   ransaction  able .  he tables are related and are linked through a field which is
        common.  his common key field in the transaction table is called the  Foreign key  and its value depends on
        the primary key values of the master table.

           CREATING A TABLE

         o create a table  click on the   ables  icon from the   atabase  indow .  here are three options in  the   ase
        that enable to create a table:
          Create Table in Design View...            Use Wizard to Create Table...        Create View...















                       Tables Icon








                                                         Options For
                                                        Creating Table



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