database - how to see a difference between entity and a column -


Sometimes I am starting to create an article when I am looking at the difference between an entity and a column. I do not know when it should be a unit or column. For example, in some games if you have a user and the user can play it himself or he can play in the group. Do you have those two different entities, users and GroupUser

apart from, for example if the user level, The situation is there and the badges they earn are part of the game. Will these be the institutions or will they be in only one unit which will be part of the user?

object can be a person ( Such as students), location (such as the name of the cell), objects (such as books), abstract concept (e.g. course, order) Can be displayed in your database and can generally become your table in the database .

Columns on the other side are attribute (s) of entity .

, badge , PlayStatus (the value may be individual or group)

Your badge however a The column can be such that it violates entity .

For example, if you have this table for user: 

  Table: User User ID Username Usstat Playstats Badge ---------- ---- ---------- ----- ----- ------ 1 Surely Active Single Private, Warrior, Platoon Leader 2 Fastchachin Active Group Private, Warrior 3 Beatthgeek Inactive Group private

badge here 1 NF (1 normal form) in the generalization rule Repeating groups must be no multi-valued column in the case. Therefore, it can be generalized: 

  Table: User User ID Username Usstatat Playstat ------ -------- -------- - - --------- 1 Activated Active Single 2 Fastmarket Active Group 3 Beat The Non-Dormant Group Table: Badge Badge Bazenam ------ -------- 1 Personal 2 Indi 3 Warrior 4 Platon Leader 5 Colonel 6 1 Star General 7 2 Star General 8 Star 3 Star Gen 9 4 Star General 10 5 Star General 11 Hero Table: Userbusiness Tree UserID badge receipt ------ -------- ------- ---- 1 1 12/01/2013 1 3 12/05/2013 1 4 1/5/2014 2 1 2/5/2014 2 3/10/2014 3 2 11/10/2013

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