Chapter 6 Many-to Many Relationship

Agenda AutoNumber Many-to-many relationship Cascaded updating and deleting Auto Lookup Parameter query Total query

Many-to-Many Relationship Many-to-many relationship has to create an intersection table The intersection table has a one-to-many relationship to each of the original tables The primary key of the intersection table is the combination of the primary keys of the two original tables

Cascade Deletion & Updating Cascade deletion –A record in the primary table is deleted, Access simultaneously deletes the corresponding records in the related table Cascade updating –The primary key in the primary table is updated, Access automatically updates the value in the corresponding records in the related table

AutoLookup Populates the corresponding fields once the primary key value is entered

Parameter Query Prompts the user for criteria when executed The prompt is enclosed in square brackets in the query design grid A parameter query may prompt for any number of variables

Total Query –Total Queries perform calculations on a group of records –Total row: contains either Group By or aggregate entry –Group By: records in the dynaset are to be grouped according to the like values –Sum Function: specifies math to be performed on that field for each group of records

Points to Remember AutoNumber Many-to-many relationship Cascaded updating and deleting Auto Lookup Parameter query Total query

Assignment