# What is the difference between 3NF and 4NF?

## What is the difference between 3NF and 4NF?

It must be in Boyce Codd Normal Form (BCNF). It should have no multi-valued dependency….Difference between BCNF and 4NF :

S.No. | BCNF | 4NF |
---|---|---|

5 | If a relation is in BCNF then it will have more redundancy as compared to 4NF. | If a relation is in 4NF then it will have less redundancy as compared to BCNF . |

## What is the relationship between the third normal form 3NF and the Boyce Codd Normal Form BCNF )?

Boyce–Codd normal form (or BCNF or 3.5NF) is a normal form used in database normalization. It is a slightly stronger version of the third normal form (3NF). BCNF was developed in 1974 by Raymond F….3NF table always meeting BCNF (Boyce–Codd normal form)

Rate type | Court | Member flag |
---|---|---|

PREMIUM-B | 2 | No |

**What is difference between 2NF and BCNF?**

2NF requires that every nonprime attribute is fully dependent on every candidate key. Since the table in your example has no nonprime attributes it cannot violate 2NF. This is the essential difference between BCNF and 2NF/3NF. BCNF requires that every attribute must be fully dependent on every key.

**What is and BCNF explain its differences with suitable example?**

BCNF is the advance version of 3NF. It is stricter than 3NF. A table is in BCNF if every functional dependency X → Y, X is the super key of the table. For BCNF, the table should be in 3NF, and for every FD, LHS is super key….EMP_DEPT_MAPPING table:

EMP_ID | EMP_DEPT |
---|---|

D394 | 283 |

D394 | 300 |

D283 | 232 |

D283 | 549 |

### What is true about relation in different normal forms?

A relation is in a “normal form” if it satisfies a certain set of constraints. First Normal Form (1NF): A relation’s underlying domains contain atomic values only. Second Normal Form (2NF): A relation’s every nonkey attribute is fully dependent on the primary key. EVERY RELATION MUST BE IN 1NF.

### What are the definitions of 1NF 2NF and 3NF?

Types of Normal Forms A relation is in 1NF if it contains an atomic value. 2NF. A relation will be in 2NF if it is in 1NF and all non-key attributes are fully functional dependent on the primary key. 3NF. A relation will be in 3NF if it is in 2NF and no transition dependency exists.

**What is non prime attribute in database?**

A candidate key, or simply a key, of a relational database is a minimal superkey. The columns in a candidate key are called prime attributes, and a column that does not occur in any candidate key is called a non-prime attribute.

**What is the Boyce-Codd normal form of a table?**

The table should be in the second normal form. There should not be any functional dependency. Boyce-Codd Normal form is a stronger generalization of third normal form. A table is in Boyce-Codd Normal form if and only if at least one of the following conditions are met for each functional dependency A → B:

## What is the difference between BCNF 2NF and 3NF?

In a table that is in the BCNF normal form, for every non-trivial functional dependency of the form A → B, A is a super-key whereas, a table that complies with 3NF should be in the 2NF, and every non-prime attribute should directly depend on every candidate key of that table.

## What is the difference between 4NF and 5NF?

4NF (Fourth Normal Form) Rules. If no database table instance contains two or more, independent and multivalued data describing the relevant entity, then it is in 4 th Normal Form. 5NF (Fifth Normal Form) Rules. A table is in 5 th Normal Form only if it is in 4NF and it cannot be decomposed into any number of smaller tables without loss of data.

**What is the difference between BCNF and 4th normal form?**

Sometimes is BCNF is also referred as 3.5 Normal Form. If no database table instance contains two or more, independent and multivalued data describing the relevant entity, then it is in 4 th Normal Form. A table is in 5 th Normal Form only if it is in 4NF and it cannot be decomposed into any number of smaller tables without loss of data.