IST 359 Lecture Notes - Lecture 2: Unique Key, Lookup Table, Check Constraint
13 Feb 2016
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Adam wang: a table is considered metadata because it provides information about other data as well, but it also depends. The data is what s located below the primary keys/what the columns are named: persistent means that data survives/outlives the process that created it. We need to make sure we save our data to override the previous save file: primary key: enforces data uniqueness by creating a unique index for the primary key columns. Unique key: make sure that no duplicate values are entered in specific columns that do not participate in a primary key: a convention is used to provide a clear structure and format; especially in team environments. This increases maintainability: yes you can control the number used by a surrogate key. The identity seed is what the number starts at and the increment is what you want the increments to go/increase by: physical domain represents the type of data in the column.
