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IST 318 – DB Administration. Intro to Relational Model, Normalization, and SQL. RDB Terminologies. RDBMS. RDBMS Functions. System Dev. Life Cycle (SDLC). SDLC Illustration. E and R. DB design should focus on organization (Management of Data), not limited to the Data (or numbers)
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IST 318 – DB Administration Intro to Relational Model, Normalization, and SQL
E and R • DB design should focus on organization (Management of Data), not limited to the Data (or numbers) • What kinds of data are needed? entities • Real world people, objects, processes, concepts • Turn into tables • How are these kinds of data are related? relationships • Turn into constraints (and sometimes tables)
Cardinality • One important type of relationship Binary relationship • The most commonly considered constraint on a binary relationships is cardinality, or number of instances that may appear through this relationship • One to one • One to many • Many to many
ER Diagram • Notice the notations for • Entities • Relationships • Cardinality constraints
Normalization – Why it’s needed? • Notice the redundancy in the dataset (modeled with a single entity/table)? • Problems (or anomalies) that can be induced • Insertion, deletion, and update anomalies • Normalization (or splitting into multiple tables) is the solution
Normalization – How to Do It? • Split a “wide” table into a number of “narrow” ones that are in the third normal form (3NF) • 1NF: data in every field is atomic, and the record has a (primary) key • 2NF: all fields depend on the whole key • 3NF: every field depends on the key directly, not through another (set of) field(s)