Corel wordperfect office 2002 User Manual
One-to-one
¾
a unique field in a table is linked to a unique field in another table. There is a
direct relationship between the tables in which there is only one record in either table for the
unique value.
One-to-many
¾
a unique value in the linked field of a parent table is linked to a non-unique
field in a child table. For example, a single customer may have many orders for products.
Many-to-one
¾
a parent table of several non-unique records is linked to a child table that
contains only unique values. For example, you could link a table that contains customer
information with a table that contains telephone numbers and area codes. There are many
customers per area code, but each customer name is unique.
To create a data model
1 Click File } New } Data model.
2 From the list box at the bottom of the Add object dialog box, choose one of the following
2 From the list box at the bottom of the Add object dialog box, choose one of the following
objects:
Tables
¾
lets you search for tables
Queries
¾
lets you search for queries
SQL
¾
lets you search for SQL
3 Click Browse
.
4 Choose the drive and folder where the object is stored.
5 Click OK.
6 Hold down CTRL, and select more than one object from the list.
7 Click Add.
8 Click Close.
5 Click OK.
6 Hold down CTRL, and select more than one object from the list.
7 Click Add.
8 Click Close.
To create a link
1 Click the field in the parent table from which you want to create a link.
2 Drag the chosen field to the field you want to link to in the child table.
2 Drag the chosen field to the field you want to link to in the child table.
If referential integrity exists between the tables, the links will appear. If referential integrity
does not already exist, the Link property dialog box will open.
3 In the Link property dialog box, choose the parent table from the Parent tables list box.
4 Choose a parent field from the Parent fields list.
5 Click the right arrow.
6 Choose the child table from the Child tables list box.
7 Choose a child field from the Child index list.
8 Click the left arrow to add it to the Child fields list.
4 Choose a parent field from the Parent fields list.
5 Click the right arrow.
6 Choose the child table from the Child tables list box.
7 Choose a child field from the Child index list.
8 Click the left arrow to add it to the Child fields list.
To remove a link
1 Click the link.
2 Click Edit } Links.
3 Choose the link from the Links box.
4 Click Unlink.
2 Click Edit } Links.
3 Choose the link from the Links box.
4 Click Unlink.
Working with forms
365