Derby
  1. Derby
  2. DERBY-1926

Provide documentation for ALTER TABLE DROP COLUMN

    Details

    • Type: Improvement Improvement
    • Status: Closed
    • Priority: Minor Minor
    • Resolution: Fixed
    • Affects Version/s: 10.3.1.4
    • Fix Version/s: 10.3.1.4
    • Component/s: Documentation
    • Labels:
      None

      Description

      The documentation will need to be updated after DERBY-1489 is committed. The reference manual will need to describe how to use the new ALTER TABLE DROP COLUMN feature to drop a column from a table.

      The documentation for the ALTER TABLE command is becoming somewhat unwieldy, so perhaps there is a way to restructure the page to make it easier and more approachable.

      In the documentation, it will be important to clearly describe the RESTRICT and CASCADE behaviors, as users may be confused by what things cause RESTRICT to refuse to drop a column. The comments in AlterTableConstantAction.java may help.

      Specifically, the documentation should note these possibly unexpected behaviors:

      • If a column is present in one or more indexes, these indexes by themselves do not cause
        RESTRICT to refuse to drop a column. Instead, the column will simply be dropped from
        the index, and if that was the last column in that index, the entire index will be dropped.
      • Explicitly named CHECK constraints will cause RESTRICT to refuse to drop a column, as
        will PRIMARY KEY, FOREIGN KEY, and UNIQUE constrants. However, an unnamed simple
        NOT NULL constraint on a column will NOT cause RESTRICT to refuse to drop it.
      1. dropCol1.diff
        3 kB
        Bryan Pendleton

        Issue Links

          Activity

          Hide
          Bryan Pendleton added a comment -

          Attached is dropCol1.diff, a proposed doc patch for the ALTER TABLE
          page in the reference guide.

          Show
          Bryan Pendleton added a comment - Attached is dropCol1.diff, a proposed doc patch for the ALTER TABLE page in the reference guide.
          Hide
          Bryan Pendleton added a comment -

          Comitted the doc patch to the docs trunk as subversion revision 462850.

          Once the updated doc appears on the web site I'll close this issue.

          Show
          Bryan Pendleton added a comment - Comitted the doc patch to the docs trunk as subversion revision 462850. Once the updated doc appears on the web site I'll close this issue.
          Hide
          Bryan Pendleton added a comment -

          Doc is now visible on the Derby site. Closing issue.

          Show
          Bryan Pendleton added a comment - Doc is now visible on the Derby site. Closing issue.

            People

            • Assignee:
              Bryan Pendleton
              Reporter:
              Bryan Pendleton
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              Dates

              • Created:
                Updated:
                Resolved:

                Development