Introduction to MySQL

1
Introduction to MySQL

• NELINET
• October 28th, 2005

2
Preliminary Definitions

• MySQL An Open Source, Enterprise-level,
  multi-threaded, relational database management
  system that stores and retrieves data using the
  Structured Query Language
• Structured Query Language (SQL) A standardized
  query language for getting information from a
  relational database.
• Relational Database A database that stores data
  in the form of relational tables as 0pposed to
  flat files.
• Database Management System (DBMS) A system that
  manages relational databases A collection of
  programs that enabling the storage, modification,
  and extraction of information from a database.

3
Cells, Rows, Tables and Databases

• Cell -- a single (scalar) value.

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Cells, Rows, Tables and Databases

• Row -- a group of scalar values representing a
  single instance of an object or event.

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Cells, Rows, Tables and Databases

• Table -- a series of rows describing separate
  objects or events.

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Cells, Rows, Tables and Databases

• Database -- a collection of related tables
  describing various facets of a group of objects
  or events.

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Relations -- One to One
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Relations -- One to Many
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Relations -- Many to Many
10
Database Design

• Sketch out your data and how the different pieces
  of data should be grouped and how they relate to
  one another. In fact, you can save yourself a
  great deal of frustration down the road if you
  take the time to think things through before you
  get started actually building the database.
• Literally draw it out in a diagram before you
  start!

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Database Design - 1st Normal Form

• Each table should have a column that identifies a
  row (primary key).
• No two rows can be identical.
• Groups of cells should never repeat.
• Each column must have a unique name.
• Each column must contain scalar values.

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Database Design - 2nd Normal Form

• Each cell in a row must depend on the primary key.

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Database Design - 3rd Normal Form

• No cell that is dependent on the primary key can
  be used to control another non-primary key cell.

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A Bad Data Model...

• Do we have a primary key?
• Do we have normality problems?

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A Better Data Model...
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Work Break!!

• Lets think about pizza...