Define Keys In Access 2010
In this article I am going to explain primary key and foreign key In Access 2010.
Keys
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A key usually consists of one field, but may consist of more than one field. There are two types of keys use in access table.
Primary Key
- Only one primary key is allowed in a table. A primary key consists of one or more fields that each record have a uniquely identify in a table.
- Primary key provide a unique identification number, id number and a code in access table.
- For Example, if we have a employee table where each employee have a unique id number. The employee id field is the primary key of the employee table.
Foreign Key
- One or more foreign key allowed in a table A foreign key contains values that correspond to values in the primary key of another table.
- For example, if we have an department table in which each department has a employee id number that corresponds to a record in a employee table. The employee id field is a foreign key of the department table.
A table relationship, shown in the Relationships window.
- A primary key, identified by the key icon next to the field name.
- A foreign key note the absence of the key icon.
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