When is a table in second normal form (2NF)?
A table is in second normal form (2NF) when it meets the following criteria:
1. It is in first normal form (1NF).
2. All non-key attributes in the table are fully dependent on the primary key. In other words, there should be no partial dependencies.
3. Any attribute that is not dependent on the primary key should be moved to a separate table.
This means that each column in the table should depend on the entire primary key of the table and not just a part of it. Therefore, if there are composite primary keys, each column in the table should depend on the entire composite key. By satisfying these conditions, the table achieves integrity and is free from any repeating groups.
A table is in second normal form (2NF) when it meets the following criteria:
1. It is already in first normal form (1NF), which means that each column in the table contains atomic values (values that cannot be divided further).
2. It does not have partial dependencies. This means that all non-key attributes (attributes that are not part of the primary key) are fully dependent on the entire primary key.
To summarize, a table is in 2NF if it satisfies 1NF and does not have any partial dependencies.