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To edit a relation In a database, tables are usually linked together in a logical way. A link between two tables is called a "relation". A relation always involves two tables ad two columns from them (one can create a relation between a table and itself for representing a tree like structure), select the line connecting the tables and right click:
The Edit Relation window will then appear:
The Left Table Name, Left Field Name, Right Table Name, Right Field Name cannot be edited in the dialog box. These contain the tables and fields you selected in the Database Diagram.
Check one of the Relation Type radio buttons:
· Only include rows where joined fields are equal - this option grabs records from both tables only where there is a match between the id_dep and iddep_emp table fields.
· Include all records from the A table and only those from the B table where joined fields are equal - with this option, all employee records will be selected, and only departments with an ID that matches the iddep_emp field from the employees_emp table.
· Include all records from the B table and only those from the A table where joined fields are equal - here, all department records are listed, and only those employees whose iddep_emp matches one of the department ID's.