Relationships between tables in Access

In this article, go with TipsMake.com to learn more about how to establish a relationship. The nn relationship is the relation between two tables, a record of table A can have multiple records matching in table B and vice versa.

In this article, go with TipsMake.com to learn more about how to establish a relationship.The nn relationship is the relation between two tables, a record of table A can have multiple records matching in table B and vice versa.

To create such a relationship, define the third table, called a join table, with the primary key including foreign keys from both Table A and Table B to divide the nn relationship into two 1-n relationships. .

Continuing with the examples in the previous tutorial, we added a tblTacgia table and a link table tblTacgiaNoi. The Author table includes the schools TacgiaID, Ten, Ho, Diachi, Dienthoai, Email, Ngaysinh.

Relationships between tables in Access Picture 1Relationships between tables in Access Picture 1
Add new table tblag has fields as shown

Often an author will work with many projects, as well as a project that can have many authors working together. As in the previous tutorials, the tblDuAn table also has an author field, so we will create a separate table that includes information about the author. So, we don't need this field in the Project table anymore.

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The tblDuAn table also has a field about Authors

Choose Tacgia school , press the delete button and you will see the following message.

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Delete the TacGia field on this table

Click Yes .

Now we will create a link board. This connector has two foreign keys as follows:

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Add 2 ID fields of the two tables to this join table

These foreign key fields will be primary keys from both tables tblTg and tblDuAn.

To create multiple keys in Access, select both of these fields, go to the Design tab , click Primary Key, the selected fields will become keys.

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The two selected fields all become keys

Save the table with the name tblTacgiaNoi.

Next, go to the Relationship in the Design tab to create a relationship by clicking Show Table.

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Add 3 tblDuAn tables, tblTacgia and tblTacgiaNoi

Select the tblDuAn, tblTacgia and tblTacgiaNoi tables, click Add to add all three tables to the desktop and close the Show Table dialog box .

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All 3 tblDuAn, tblTacgia and tblTacgiaNoi tables are added to the screen

Using the mouse to click and hold the TacgiaID field in tblTacgia table , drag to the TacgiaID field you want to connect to the table tblTacgiaNoi. When you release the mouse, Access opens the Edit Relationships window . Note, the relationship that is creating Access will be considered a 1-n relationship. Click the Cascade Update box and click Create:

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Pulling together two TacgiaID fields of two tables will display the Edit Relationships dialog box

Result:

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Next, drag the DuAnID field from the tblDuAn table to the DuAnID field of the tableTableGoogle, and check the Enforce Referential Integrity box and Cascade Update Related Fields .

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Drag the two DuAnID fields of the two tables together to display the Edit Relationships dialog box

And this is the relationship we want to establish:

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Relationship nn

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