a) Set the relationship of the table:
i. There is a relationship between data in different tables (the same properties in different tables)
II. There are three relationships between tables:
1. One-to-one: Need to match the value of only one recorded keyword field in a new table matches a separate value of the relevant fields in the existing table.
2. One-to-many: The primary key field of the new table is unique, but the value in the external key of the new table can match multiple items in the relevant fields in the existing database. In this type, the fields related to the existing database have multiple pairs of relationships with the primary key fields of the new database.
3. Multiple: A completely unlimited relationship, there is no unique relationship between the existing table or the keyword field in the new table, and the external key field of the two tables can contain a duplicate value.
III. Use the relationship between tool settings.
1. Find the core table
2. Edit the relationship, pay attention to the integrity (external code relationship)
3. Access requires two fields with fully identical data types to participate in the relationship. In the case where the field data type is "numbers", the "Field Size" attribute of the two fields must be the same. For example, you cannot create a relationship between the field of the automatic number type (using long integer data type) and the field containing bytes, integer, single precision, double precision or currency data.
b) modification of the database structure
i. Make backup before modifying (back up the entire database or single table)
II. Modify relationship
1. Delete relationship
2. Editing relationship
3. Add relationship
c) Modification of the table structure
i. Mainly a modification of fields (modifying other objects)
1. Modify the field name: Open the modification with design view
2. Insert a new field:
3. Move fields
4. Copy field
5. Delete fields
6. Modify Field Properties
7. Change the column keyword
d) Use and editing of the database
i. Modifications to format
II. Modification of the tuple
