Existence checks

• Make use of the existence checking defined  here
• Always check for existence when adding new objects to the database (see example below)

IF NOT EXISTS
              (
              SELECT TOP 1
                     1
              FROM
                   sys.all_columns c
                   JOIN sys.tables t
                      ON t.object_id = c.object_id
              WHERE t.name = 'EmployeeLeave'
                    AND c.name = 'ActionStatus')
   BEGIN
      ALTER TABLE EmployeeLeave
      ADD
                  ActionStatus INT
END

• Also check for existence when editing a database object (see example below)

IF EXISTS
              (
              SELECT TOP 1
                     1
              FROM
                   sys.all_columns c
                   JOIN sys.tables t
                      ON t.object_id = c.object_id
              WHERE t.name = 'EmployeeLeave'
                    AND c.name = 'ActionStatus')
   BEGIN
      ALTER TABLE EmployeeLeave
      ALTER COLUMN ActionStatus NVARCHAR(2) NOT NULL
END