CC SQL 1-introduction

Card Set Information

CC SQL 1-introduction
2012-04-07 08:22:11
CC SQL introduction

CC SQL 1-introduction
Show Answers:

  1. what is a database?
    • 1. is acollection of data stored in some organized fashion.
    • 2. a container (usally a file or set of files) to store organized data
  2. tables?
    a structured list of data of a specific type
  3. Schema?
    information about database and table layout and properties

    • Note
    • Schema or Database? Occasionally schema is used as a synonym for database (and schemata as a synonym for databases). While unfortunate, it is usually clear from the context which meaning of schema is intended. In this book, schema will refer to the definition given here.
  4. column?
    a single field in a table. All tables are made up of one or more columns
  5. datatype?
    A type of allowed data. Every table column has associated datype that restricts (or allows) specific data in that column.
  6. row?
    a record in a table
  7. primary key?
    a column (or set of columns) whose values unquely identify every row in a table

    • Any column in a table can be established as the primary key, as long as it meets the following conditions:
    • 1. No two rows can have the same primary key value.
    • 2. Every row must have a primary key value (primary key columns may not allow NULL values).