{"id":479,"date":"2022-08-23T17:01:15","date_gmt":"2022-08-23T16:01:15","guid":{"rendered":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/?page_id=479"},"modified":"2022-08-23T17:40:04","modified_gmt":"2022-08-23T16:40:04","slug":"normalisation","status":"publish","type":"page","link":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/normalisation\/","title":{"rendered":"Normalisation"},"content":{"rendered":"

Normalisation is the process of dividing a flat file database into smaller tables\u00a0\u200b<\/p>\n

In other words, normalisation removes the deletion, insertion and update anomalies from a database table.<\/span>
\nA table which is in unnormalised form is a flat file table.<\/p>\n

Example<\/strong>\u200b<\/p>\n

A school stores\u00a0all of\u00a0it’s\u00a0course details in record cards with one record card for\u00a0each course. A student may take several courses, and teachers may teach more than one course. A sample record card is shown below<\/p>\n

\"\"<\/a><\/p>\n

 <\/p>\n

Step 1: List the attributes<\/strong><\/p>\n

\u200bcourse_id<\/p>\n

course_title<\/p>\n

teacher_id<\/p>\n

teacher_name<\/p>\n

pupil_id<\/p>\n

pupil_name<\/p>\n

DOB<\/p>\n

tutor_group<\/p>\n

grade<\/p>\n

Step 2: Identify the Primary key and underline it<\/u><\/strong><\/p>\n

\u200bcourse_id<\/u><\/p>\n

course_title<\/p>\n

teacher_id<\/p>\n

teacher_name<\/p>\n

pupil_id<\/p>\n

pupil_name<\/p>\n

DOB<\/p>\n

tutor_group<\/p>\n

grade<\/p>\n

Step 3: Identify the repeating groups – using the primary key, decided if their is one value linked to the primary key or many values.<\/strong><\/p>\n

\"\"<\/a><\/p>\n

\u200bcourse_id<\/u><\/p>\n

course_title 1<\/strong><\/p>\n

teacher_id\u00a01<\/strong><\/p>\n

teacher_name\u00a01<\/strong><\/p>\n

pupil_id\u00a0m<\/strong><\/p>\n

pupil_name\u00a0m<\/strong><\/p>\n

DOB\u00a0m<\/strong><\/p>\n

tutor_group\u00a0m<\/strong><\/p>\n

grade\u00a0m<\/strong><\/p>\n

Linked to the Primary Key course_id, there is 1 course title and 1 teacher etc, but there are many pupil_id’s and pupil_names etc.<\/p>\n

Step 4: Remove the repeating groups to a new entity – make sure you name both entity tables<\/strong><\/p>\n

Course<\/strong> (course_id<\/u><\/p>\n

course_title<\/p>\n

teacher_id<\/p>\n

teacher_name )<\/p>\n

Pupil<\/strong> (pupil_id<\/p>\n

pupil_name<\/p>\n

DOB<\/p>\n

tutor_group<\/p>\n

grade)<\/p>\n

Step 5: Underline the new Primary key in the second entity and add the Foreign key to link both tables together and mark it with an asterisks *.<\/strong><\/p>\n

Course<\/strong> (course_id<\/u><\/p>\n

course_title<\/p>\n

teacher_id<\/p>\n

teacher_name )<\/p>\n

Pupil<\/strong> (pupil_id<\/u><\/p>\n

pupil_name<\/p>\n

DOB<\/p>\n

tutor_group<\/p>\n

grade<\/p>\n

course_id*)<\/p>\n","protected":false},"excerpt":{"rendered":"

Normalisation is the process of dividing a flat file database into smaller tables\u00a0\u200b In other words, normalisation removes the deletion, insertion and update anomalies from a database table. A table which is in unnormalised form is a flat file table. Example\u200b A school stores\u00a0all of\u00a0it’s\u00a0course details in record cards with one record card for\u00a0each course. […]<\/p>\n","protected":false},"author":79984,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-479","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/pages\/479","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/users\/79984"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/comments?post=479"}],"version-history":[{"count":14,"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/pages\/479\/revisions"}],"predecessor-version":[{"id":494,"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/pages\/479\/revisions\/494"}],"wp:attachment":[{"href":"https:\/\/blogs.glowscotland.org.uk\/glowblogs\/phsn5computingscience\/wp-json\/wp\/v2\/media?parent=479"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}