SQL design tool

database algebra

Field Type

  • int: integer; length: how many digits.
  • AI: auto incremental
  • varchar: characters; length: how many characters to enter (128)
  • date: enter it yourself or current timestamp
  • float(n,d): n for length, and d for decimal point from right

Prime vs Unique:

  • Prime for data linking
  • Unique for indexing and searching