First Normal Form (1FN)

First Normal Form (1FN)

1. Steps for elaboration

   • Remove repetitive groups from individual tables.
   • Create a separate table for each group of related data.
   • Identify each group of data related of data related to a primary key.

2. Features

   • Atomic attributes
     • The phones field cannot store multiple attributes.
   • The table contains a unique primary key
     • Identification document of an individual or vehicle.
   • The primary key does not contain null attributes
     • Individual u/or vehicle without identificatión.
   • There should be no variation in the number of columns
     • Equality of columns in a row.
   • Functional dependency
     • Non-key fields must be identified by the key.
   • There must be an independence of the order of both rows and columns

3. To take into account

   • A 1FN table can still contain both partial and transitive dependencies.
     • Transitive Dependency: This is one in which one attribute is functionally dependent on another non-key attribute.
     • Partial Dependency: This is one in which on attribute is functionally dependent on a part of a multi-attribute primary key.
   • Violation of any of these conditions would mean that the table is not strictly relational, and therefore is not in 1FN.

4. It consists of optimizing the database and deleting repeated groups (does not allow the use of more than one repeated data in the tables

5. Conclusion: A table is in 1FN when all key attributes are defined and when all other attributes depend on the primary key. Naturally, a table with a single attribute primary key cannot exhibit partial dependencies.

6. Objective: Get good decompositions, from the properties of them infromation.

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