UPDATE

• UPDATE


  Changing data (rows) in the database
• UPDATE


  Some uses of UPDATE and the syntax
• UPDATE table SET (c1 = v1, c2 = v2, ...) WHERE…


  • Which table to change
  • Which columns to change data
  • What's the [optional] condition as to which rows we change?
• Why WHERE PetID =109 and not WHERE Name = 'Slippery Jim'?


  • PetID is the primary key
  • The primary key is a unique way to reference the specific instance of an entity
  • Primary key will always be unique – name can't be guaranteed!
• The condition specified in the WHERE clause determines how many rows will be updated
• Without the WHERE clause will update all records!
• UPDATE Warning! No WHERE clause means all rows match. Be careful - If you omit the WHERE clause, ALL records will be updated!
• Both are acceptable, but best to stick to method (b) for consistency
• We put quotes around textual values
• Numerical values can be quoted or not
• Escaping Quotes: Use the escape character (like with Java): \