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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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