Divides your information into subject-based tables to reduce redundant data.
In the Product Table, the information contents are all related to product like Cost, Selling Price, Quantity, Reorder level, etc. In the Supplier Table, the information contents are all related to supplier like Company Name, Address, City, etc. It reduces redundant data.
Provides the database management system with the information it requires to join the information in the tables together as needed.
In the two tables, there is one field with same name i.e. Supplier Number which can link the tables together to give join information. Then we will know that the particular product is supplied by which supplier.
In the Product Table, the information contents are all related to product like Cost, Selling Price, Quantity, Reorder level, etc. In the Supplier Table, the information contents are all related to supplier like Company Name, Address, City, etc. It reduces redundant data.
Provides the database management system with the information it requires to join the information in the tables together as needed.
In the two tables, there is one field with same name i.e. Supplier Number which can link the tables together to give join information. Then we will know that the particular product is supplied by which supplier.
For Q1, you may also say that each table is only specifically about one subject only. So in the Product table, you won't see any information about the supplier of the product, such as name, phone no., address, etc. As you have answered in the 2nd paragraph, the supplier ID allows you to link the product record to the related supplier record in another table.
回覆刪除In this way, information is only written in the database once, which prevents redundancy or duplication of data. This is because if a company supplies 35 products, their name, address, phone no. and so on will still be recorded in one supplier record only, instead of listed on 35 product records.
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