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SALARY_HIST entity, which stores the salary amount and the date when the new salary goes into effect” (Coronel, 2013).Diagram a possible 1:M solution that will hold salary history data, job history, and traininghistory for each employee through the use of graphical tools. Note: The graphically depicted solution is not included in the required page length.
Assignment 4 Database Modeling and Normalization 6Plan each step of the normalization process to ensure the 3NF level of normalization using the selected five (5) entities of the personnel database solution. Document each step of the process and justify your assumptions in the process.Normalization is a procedure of formulating the data in the database. Normalization is an organized method of breaking up tables to eliminate data redundancy and undesirable characteristics. Normalization main reason is for eliminating useless data and making sure the data dependencies make sense and logically stored. Without normalization, it becomes difficult to handle and update the database, without facing data loss. Normalization follows three basic steps, each building on the last. The first of these steps is the first normal form. First normal form (1NF) sets the rules for database normalization and relates to a single table within a relational database system. The first
Assignment 4 Database Modeling and Normalization 7normal form states that every column in the table must be unique, separate tables must be createdfor each set of related data, each table must be identified with a unique column or concatenated columns called the primary key. The first normal form (1NF) involves the removal of repeating groups. For each repeating group encountered, the repeating group is moved to a separate table. “No rows may be duplicated, no columns may be duplicated, no row/column intersections contain a null value, no row/column intersections contain multivalued fields” (Janssen, 2014). Second normal form (2NF) is the second step in normalizing a database. 2NF builds on the first normal form (1NF). A 1NF table is in 2NF form if and only if all of its non-prime attributes are functionally dependent on the whole of every candidate key” (Janssen, 2014). A table that is in first normal form (1NF) must meet additional criteria if it is to qualify for second normal form. To get tables into the second normal form, fields must be analyzed to show the relation to the primary key. There is no redundancy of data (all data is stored in only one place). Data dependencies are logical (all related data items are stored together). A 1NF table is in 2NF form if and only if all of its non-prime attributes are functionally dependent on the whole of every candidate key” (Janssen, 2014).Third normal form (3NF) is the third step in normalizing a database and it builds on the first and second normal forms, 1NF and 2NF. The purpose of going to 3NF is that on this normal form, functional dependencies are eliminated on non-key fields. The rule is to remove a new