هل يوجد أحد يشرح ال 3 normalization
تاريخ المشاركة 22 November 2004 - 10:57 AM
A series of steps followed to obtain a database design that allows for efficient access and storage of data. These steps reduce data redundancy and the chances of data becoming inconsistent.
First Normal Form
eliminates repeating groups by putting each into a separate table and connecting them with a one-to-many relationship.
Second Normal Form
eliminates functional dependencies on a partial key by putting the fields in a separate table from those that are dependent on the whole key.
Third Normal Form
eliminates functional dependencies on non-key fields by putting them in a separate table. At this stage, all non-key fields are dependent on the key, the whole key and nothing but the key.
Fourth Normal Form
separates independent multi-valued facts stored in one table into separate tables.
Fifth Normal Form
breaks out data redundancy that is not covered by any of the previous normal forms.