How to normalize your tables
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The document provides steps to normalize a course enrollment table into third normal form by splitting it into multiple tables, identifying dependencies between fields, and creating primary and foreign keys to define relationships between the tables. It begins with the course enrollment table and walks through splitting it into tables for courses, students, and faculty while ensuring each table has a primary key and relationships are defined.
How to normalize your tables
- 1. How to normalize your tables Keyvan Bashash This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
- 2. Course enrollment table CrsID StID Semester FacultyID StName CrsName FacultyN Date 420 111,112 fall 122 Ali,Mark Linux,Java ConEd 10-12-2018 722 111 fall 222 Ali Swimming Physical 11-10-2018
- 3. Step 1: get into first normalization format - In each filed there should be only one value of that type - if you see multiple values in one field, duplicate the record to cover each value. {in red} - sure you will have some records that looks same with just one field different - in fact you shouldn’t have any field in any record empty whilst you don’t have data CrsID StID Semester FacultyID StName CrsName FacultyN Date 420 111 fall 122 Ali Linux ConEd 10-12-2018 420 112 fall 122 Mark Java ConEd 10-12-2018 722 111 fall 222 Ali Swimming Physical 11-10-2018
- 4. Step 2: get into second normalization format - Find the determinant with full dependency. It means that all other fields should be depended on this set of fields. {CrsID, StID} - Now find all partial dependencies, it means all fields that are depended on part of our full determinant.{CrsID-->Semester, FacultyID, CrsName, FacultyN} - For each part of our main determinant that has partial dependencies, create a new table, copy the determinant and move all other dependent fields to new table. - In your new tables, the part of main table’s determinant would be a PRIMARY-KEY CrsID StID Semester FacultyID StName CrsName FacultyN Date 420 111 fall 122 Ali Linux ConEd 10-12-2018 420 112 fall 122 Mark Java ConEd 12-11-2018 722 111 fall 222 Ali Swimming Physical 11-10-2018
- 5. CrsID Semester FacultyID CrsName FacultyN 420 fall 122 Linux ConEd 420 fall 122 Java ConEd 722 fall 222 Swimming Physical StID StName 111 Ali 112 Mark 111 Ali CrsID StID Date 420 111 10-12-2018 420 112 12-11-2018 722 111 11-10-2018
- 6. Step 3: get into third normalization format -Now check in your tables if you have any transitive dependencies, it means any field depends on any other field than the determinant.{FacultyN-->FacultyID} -If you have such thing, then separate all fields as a new table. -Find the primary key in new table, should be the determinant in main table. -Keep this primary key as foreign key in main table.
- 7. CrsID Semester FacultyID CrsName 420 fall 122 Linux 420 fall 122 Java 722 fall 222 Swimming StID StName 111 Ali 112 Mark 111 Ali CrsID StID Date 420 111 10-12-2018 420 112 12-11-2018 722 111 11-10-2018 FacultyID FacultyN 122 ConEd 122 ConEd 222 Physical
- 8. Step 4: Create relationships Now all repeated fields in two tables should be used to make a relationship between these tables. Check if: -All relations are one-to-one or one-to-many, No many-to-many relationship -All tables must have at least one relationship if not you made a mistake, restart and do re-work...
- 9. CrsID Semester FacultyID CrsName 420 fall 122 Linux 420 fall 122 Java 722 fall 222 Swimming StID StName 111 Ali 112 Mark 111 Ali CrsID StID Date 420 111 10-12-2018 420 112 12-11-2018 722 111 11-10-2018 FacultyID FacultyN 122 ConEd 122 ConEd 222 Physical