Databases; tools and techniques. Tables.

Databases; tools and techniques. Tables.

1. Table Characterisitics

   • Rows & Columns
     • Records & Fields
     • Row: Record
     • Column: Field
   • Field Types
     • Alphabetic
       • Text
       • Memo
     • Web
       • Hyperlink
     • Logical
       • Yes/No
       • True/False
     • Numeric
       • Numbers
       • Currency
       • Dates
       • Time
     • Lookup Wizards
       • Dropdown
       • VLOOKUP
   • Field Size
     • Byte
     • Integer
     • Long Interger
     • Single
     • Double
     • Decimal
   • Field Formats
     • Fixed
     • Decimal Places
   • Default Values

2. Validation

   • Checking for errors
   • Applies to a range
   • Correct Format
     • Postcode
       • Input Mask
       • DD/MM/YYYY
   • Correct Field Size
   • Checks
     • Digits
       • The last one or two digits in a code are used to check the other digits are correct
       • Barcode reader
     • Format
       • Checks the data is in the right format
       • A National Insurance number
     • Length
       • Checks the data isn't too short or too long
       • A password
     • Prescence
       • Checks that data has been entered into a field
       • In most databases a key field cannot be left blank
     • Range
       • Checks that a value falls within the specified range
       • Number of hours worked must be less than 50 and more than 0
     • Spelling
       • Looks up words in a dictionary
       • Word processing
   • Lookup Table
     • Looks up acceptable values in a table
     • There are only seven possible days of the week

3. Records

   • Add
     • Manually
     • External Source
       • Spreadsheet
   • Edit
   • Delete

4. Indexing

   • Primary Key
     • Unique Idnetifying
   • Foreign Key
     • A way of linking Primary Keys

5. Relationships

   • One to Many
   • One to One
   • Many to Many