Exemplo n.º 1
0
  /** Throws if the table is referenced in a foreign key constraint. */
  private void checkTableIsReferenced(Table toDrop) throws HsqlException {

    Constraint[] constraints = toDrop.getConstraints();
    Constraint currentConstraint = null;
    Table refTable = null;
    boolean isRef = false;
    boolean isSelfRef = false;
    int refererIndex = -1;

    for (int i = 0; i < constraints.length; i++) {
      currentConstraint = constraints[i];

      if (currentConstraint.getType() != Constraint.MAIN) {
        continue;
      }

      refTable = currentConstraint.getRef();
      isRef = (refTable != null);
      isSelfRef = (isRef && toDrop.equals(refTable));

      if (isRef && !isSelfRef) {

        // cover the case where the referencing table
        // may have already been dropped
        for (int k = 0; k < tTable.size(); k++) {
          if (refTable.equals(tTable.get(k))) {
            refererIndex = k;

            break;
          }
        }

        if (refererIndex != -1) {
          throw Trace.error(
              Trace.TABLE_REFERENCED_CONSTRAINT,
              Trace.Database_dropTable,
              new Object[] {currentConstraint.getName().name, refTable.getName().name});
        }
      }
    }
  }
Exemplo n.º 2
0
  /**
   * Drops the specified user-defined view or table from this Database object.
   *
   * <p>The process of dropping a table or view includes:
   *
   * <OL>
   *   <LI>checking that the specified Session's currently connected User has the right to perform
   *       this operation and refusing to proceed if not by throwing.
   *   <LI>checking for referential constraints that conflict with this operation and refusing to
   *       proceed if they exist by throwing.
   *   <LI>removing the specified Table from this Database object.
   *   <LI>removing any exported foreign keys Constraint objects held by any tables referenced by
   *       the table to be dropped. This is especially important so that the dropped Table ceases to
   *       be referenced, eventually allowing its full garbage collection.
   *   <LI>
   * </OL>
   *
   * <p>
   *
   * @param name of the table or view to drop
   * @param ifExists if true and if the Table to drop does not exist, fail silently, else throw
   * @param isView true if the name argument refers to a View
   * @param session the connected context in which to perform this operation
   * @throws SQLException if any of the checks listed above fail
   */
  void dropTable(String name, boolean ifExists, boolean isView, Session session)
      throws SQLException {

    Table toDrop = null;
    int dropIndex = -1;
    int refererIndex = -1;
    Enumeration constraints = null;
    Constraint currentConstraint = null;
    Table refTable = null;
    boolean isRef = false;
    boolean isSelfRef = false;

    for (int i = 0; i < tTable.size(); i++) {
      toDrop = (Table) tTable.get(i);

      if (toDrop.equals(name, session) && isView == toDrop.isView()) {
        dropIndex = i;

        break;
      } else {
        toDrop = null;
      }
    }

    if (dropIndex == -1) {
      if (ifExists) {
        return;
      } else {
        throw Trace.error(isView ? Trace.VIEW_NOT_FOUND : Trace.TABLE_NOT_FOUND, name);
      }
    }

    constraints = toDrop.getConstraints().elements();

    while (constraints.hasMoreElements()) {
      currentConstraint = (Constraint) constraints.nextElement();

      if (currentConstraint.getType() != Constraint.MAIN) {
        continue;
      }

      refTable = currentConstraint.getRef();
      isRef = (refTable != null);
      isSelfRef = (isRef && toDrop.equals(refTable));

      if (isRef && !isSelfRef) {

        // cover the case where the referencing table
        // may have already been dropped
        for (int k = 0; k < tTable.size(); k++) {
          if (refTable.equals(tTable.get(k))) {
            refererIndex = k;

            break;
          }
        }

        if (refererIndex != -1) {

          // tony_lai@users 20020820 - patch 595156
          throw Trace.error(
              Trace.INTEGRITY_CONSTRAINT_VIOLATION,
              currentConstraint.getName().name + " table: " + refTable.getName().name);
        }
      }
    }

    tTable.remove(dropIndex);
    removeExportedKeys(toDrop);
    aAccess.removeDbObject(toDrop.getName());
    triggerNameList.removeOwner(toDrop.tableName);
    indexNameList.removeOwner(toDrop.tableName);
    toDrop.drop();
    session.setScripting(!toDrop.isTemp());
    session.commit();
  }