s:
· Information about user
- «ID» - a unique key that identifies the corresponding object.
- «Name», «Nickname» - attributes determine personality of the user in real life and in the forum.
- «Adress», «e-mail» - contact Information.
- «Pass» - personal data with which the user logs in to the forum.
- «Country», «Status», «Regestration date» - characteristics of the user.
· Information about topics
- «ID» - a unique key that identifies the corresponding object.
- «Topic name» - topic name
- «The author» - the author who created the topic.
- «Number of replies», «Time», «Open / Closed» - characteristics of Topics.
· Information about messages
- «ID» - a unique key that identifies the corresponding object.
- «The author» - the author who created the message.
- «Тема» - topic, where this message is.
- «Content" - the text field that contains the message text.
- «Time» - time when the message was written.
· Information about violations
- «User" - the user who made the violations.
- «Topic" - Topic where a punishment has occurred.
- «Description violations" - an explanation of issue of violations.
- «Content" - the text field that contains the message text.
· Information about user s online history
- «User code» - a unique key that identifies the corresponding object.
- «Start Time«, »End Time" - characterize the the length of the sessions.
· Information about User s friends
- «Man" - a unique key that identifies the corresponding object.
- «Friend» - nickname by another user
3.1 The transition to the first normal form
Pic 1
the transition to the first normal form we should ensure that on the intersection of rows and columns have only one meaning. We use the method of exclusion repeating groups: fill the empty cells of the table duplicates the relevant information about the recurring groups and define the primary key of the result.
3.2 The transition to the second normal form
the following links :: and topics on the forum a lot, but each message or theme have their only carrier, so communication will be 1: N. One at the the user code, N at a field and the author's name in other tables.message belongs to a certain topic. The punishment occurs in one of the forum. Link will be 1: N. One at the Topics, N at the fields with the code Topics in other tables ..
.3 The transition to the second normal form
connection, the following functional dependencies: Violations? Theme, Theme? Message? Message violation.Violation? Message is transitive, therefore, the link is not in 3NF., The table is divided into two tables. violations: Theme ...
