sybasebuilder.java

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        {
            writeQuotationOnStatement();
        }
        super.processChanges(currentModel, desiredModel, changes, params);
    }

    /**
     * {@inheritDoc}
     */
    protected void processTableStructureChanges(Database currentModel,
                                                Database desiredModel,
                                                Table    sourceTable,
                                                Table    targetTable,
                                                Map      parameters,
                                                List     changes) throws IOException
    {
        // First we drop primary keys as necessary
        for (Iterator changeIt = changes.iterator(); changeIt.hasNext();)
        {
            TableChange change = (TableChange)changeIt.next();

            if (change instanceof RemovePrimaryKeyChange)
            {
                processChange(currentModel, desiredModel, (RemovePrimaryKeyChange)change);
                changeIt.remove();
            }
            else if (change instanceof PrimaryKeyChange)
            {
                PrimaryKeyChange       pkChange       = (PrimaryKeyChange)change;
                RemovePrimaryKeyChange removePkChange = new RemovePrimaryKeyChange(pkChange.getChangedTable(),
                                                                                   pkChange.getOldPrimaryKeyColumns());

                processChange(currentModel, desiredModel, removePkChange);
            }
        }


        HashMap columnChanges = new HashMap();

        // Next we add/remove columns
        for (Iterator changeIt = changes.iterator(); changeIt.hasNext();)
        {
            TableChange change = (TableChange)changeIt.next();

            if (change instanceof AddColumnChange)
            {
                AddColumnChange addColumnChange = (AddColumnChange)change;

                // Oracle can only add not insert columns
                if (addColumnChange.isAtEnd())
                {
                    processChange(currentModel, desiredModel, addColumnChange);
                    changeIt.remove();
                }
            }
            else if (change instanceof RemoveColumnChange)
            {
                processChange(currentModel, desiredModel, (RemoveColumnChange)change);
                changeIt.remove();
            }
            else if (change instanceof ColumnAutoIncrementChange)
            {
                // Sybase has no way of adding or removing an IDENTITY constraint
                // Thus we have to rebuild the table anyway and can ignore all the other 
                // column changes
                columnChanges = null;
            }
            else if ((change instanceof ColumnChange) && (columnChanges != null))
            {
                // we gather all changed columns because we can use the ALTER TABLE ALTER COLUMN
                // statement for them
                ColumnChange columnChange     = (ColumnChange)change;
                ArrayList    changesPerColumn = (ArrayList)columnChanges.get(columnChange.getChangedColumn());

                if (changesPerColumn == null)
                {
                    changesPerColumn = new ArrayList();
                    columnChanges.put(columnChange.getChangedColumn(), changesPerColumn);
                }
                changesPerColumn.add(change);
            }
        }
        if (columnChanges != null)
        {
            for (Iterator changesPerColumnIt = columnChanges.entrySet().iterator(); changesPerColumnIt.hasNext();)
            {
                Map.Entry entry            = (Map.Entry)changesPerColumnIt.next();
                Column    sourceColumn     = (Column)entry.getKey();
                ArrayList changesPerColumn = (ArrayList)entry.getValue();

                // Sybase does not like us to use the ALTER TABLE ALTER statement if we don't actually
                // change the datatype or the required constraint but only the default value
                // Thus, if we only have to change the default, we use a different handler
                if ((changesPerColumn.size() == 1) && (changesPerColumn.get(0) instanceof ColumnDefaultValueChange))
                {
                    processChange(currentModel,
                                  desiredModel,
                                  (ColumnDefaultValueChange)changesPerColumn.get(0));
                }
                else
                {
                    Column targetColumn = targetTable.findColumn(sourceColumn.getName(),
                                                                 getPlatform().isDelimitedIdentifierModeOn());

                    processColumnChange(sourceTable, targetTable, sourceColumn, targetColumn);
                }
                for (Iterator changeIt = changesPerColumn.iterator(); changeIt.hasNext();)
                {
                    ((ColumnChange)changeIt.next()).apply(currentModel, getPlatform().isDelimitedIdentifierModeOn());
                }
            }
        }
        // Finally we add primary keys
        for (Iterator changeIt = changes.iterator(); changeIt.hasNext();)
        {
            TableChange change = (TableChange)changeIt.next();

            if (change instanceof AddPrimaryKeyChange)
            {
                processChange(currentModel, desiredModel, (AddPrimaryKeyChange)change);
                changeIt.remove();
            }
            else if (change instanceof PrimaryKeyChange)
            {
                PrimaryKeyChange    pkChange    = (PrimaryKeyChange)change;
                AddPrimaryKeyChange addPkChange = new AddPrimaryKeyChange(pkChange.getChangedTable(),
                                                                          pkChange.getNewPrimaryKeyColumns());

                processChange(currentModel, desiredModel, addPkChange);
                changeIt.remove();
            }
        }
    }


    /**
     * Processes the addition of a column to a table.
     * 
     * @param currentModel The current database schema
     * @param desiredModel The desired database schema
     * @param change       The change object
     */
    protected void processChange(Database        currentModel,
                                 Database        desiredModel,
                                 AddColumnChange change) throws IOException
    {
        print("ALTER TABLE ");
        printlnIdentifier(getTableName(change.getChangedTable()));
        printIndent();
        print("ADD ");
        writeColumn(change.getChangedTable(), change.getNewColumn());
        printEndOfStatement();
        change.apply(currentModel, getPlatform().isDelimitedIdentifierModeOn());
    }

    /**
     * Processes the removal of a column from a table.
     * 
     * @param currentModel The current database schema
     * @param desiredModel The desired database schema
     * @param change       The change object
     */
    protected void processChange(Database           currentModel,
                                 Database           desiredModel,
                                 RemoveColumnChange change) throws IOException
    {
        print("ALTER TABLE ");
        printlnIdentifier(getTableName(change.getChangedTable()));
        printIndent();
        print("DROP ");
        printIdentifier(getColumnName(change.getColumn()));
        printEndOfStatement();
        change.apply(currentModel, getPlatform().isDelimitedIdentifierModeOn());
    }

    /**
     * Processes the removal of a primary key from a table.
     * 
     * @param currentModel The current database schema
     * @param desiredModel The desired database schema
     * @param change       The change object
     */
    protected void processChange(Database               currentModel,
                                 Database               desiredModel,
                                 RemovePrimaryKeyChange change) throws IOException
    {
        // TODO: this would be easier when named primary keys are supported
        //       because then we can use ALTER TABLE DROP
        String tableName         = getTableName(change.getChangedTable());
        String tableNameVar      = "tn" + createUniqueIdentifier();
        String constraintNameVar = "cn" + createUniqueIdentifier();

        println("BEGIN");
        println("  DECLARE @" + tableNameVar + " nvarchar(60), @" + constraintNameVar + " nvarchar(60)");
        println("  WHILE EXISTS(SELECT sysindexes.name");
        println("                 FROM sysindexes, sysobjects");
        print("                 WHERE sysobjects.name = ");
        printAlwaysSingleQuotedIdentifier(tableName);
        println(" AND sysobjects.id = sysindexes.id AND (sysindexes.status & 2048) > 0)");
        println("  BEGIN");
        println("    SELECT @" + tableNameVar + " = sysobjects.name, @" + constraintNameVar + " = sysindexes.name");
        println("      FROM sysindexes, sysobjects");
        print("      WHERE sysobjects.name = ");
        printAlwaysSingleQuotedIdentifier(tableName);
        print(" AND sysobjects.id = sysindexes.id AND (sysindexes.status & 2048) > 0");
        println("    EXEC ('ALTER TABLE '+@" + tableNameVar + "+' DROP CONSTRAINT '+@" + constraintNameVar + ")");
        println("  END");
        print("END");
        printEndOfStatement();
        change.apply(currentModel, getPlatform().isDelimitedIdentifierModeOn());
    }

    /**
     * Processes the change of the default value of a column. Note that this method is only
     * used if it is the only change to that column.
     * 
     * @param currentModel The current database schema
     * @param desiredModel The desired database schema
     * @param change       The change object
     */
    protected void processChange(Database                 currentModel,
                                 Database                 desiredModel,
                                 ColumnDefaultValueChange change) throws IOException
    {
        print("ALTER TABLE ");
        printlnIdentifier(getTableName(change.getChangedTable()));
        printIndent();
        print("REPLACE ");
        printIdentifier(getColumnName(change.getChangedColumn()));

        Table  curTable  = currentModel.findTable(change.getChangedTable().getName(), getPlatform().isDelimitedIdentifierModeOn());
        Column curColumn = curTable.findColumn(change.getChangedColumn().getName(), getPlatform().isDelimitedIdentifierModeOn());

        print(" DEFAULT ");
        if (isValidDefaultValue(change.getNewDefaultValue(), curColumn.getTypeCode()))
        {
            printDefaultValue(change.getNewDefaultValue(), curColumn.getTypeCode());
        }
        else
        {
            print("NULL");
        }
        printEndOfStatement();
        change.apply(currentModel, getPlatform().isDelimitedIdentifierModeOn());
    }

    /**
     * Processes a change to a column.
     * 
     * @param sourceTable  The current table
     * @param targetTable  The desired table
     * @param sourceColumn The current column
     * @param targetColumn The desired column
     */
    protected void processColumnChange(Table  sourceTable,
                                       Table  targetTable,
                                       Column sourceColumn,
                                       Column targetColumn) throws IOException
    {
        Object oldParsedDefault = sourceColumn.getParsedDefaultValue();
        Object newParsedDefault = targetColumn.getParsedDefaultValue();
        String newDefault       = targetColumn.getDefaultValue();
        boolean defaultChanges  = ((oldParsedDefault == null) && (newParsedDefault != null)) ||
                                  ((oldParsedDefault != null) && !oldParsedDefault.equals(newParsedDefault));

        // Sybase does not like it if there is a default spec in the ALTER TABLE ALTER
        // statement; thus we have to change the default afterwards
        if (newDefault != null)
        {
            targetColumn.setDefaultValue(null);
        }
        if (defaultChanges)
        {
            // we're first removing the default as it might make problems when the
            // datatype changes
            print("ALTER TABLE ");
            printlnIdentifier(getTableName(sourceTable));
            printIndent();
            print("REPLACE ");
            printIdentifier(getColumnName(sourceColumn));
            print(" DEFAULT NULL");
            printEndOfStatement();
        }
        print("ALTER TABLE ");
        printlnIdentifier(getTableName(sourceTable));
        printIndent();
        print("MODIFY ");
        writeColumn(sourceTable, targetColumn);
        printEndOfStatement();
        if (defaultChanges)
        {
            print("ALTER TABLE ");
            printlnIdentifier(getTableName(sourceTable));
            printIndent();
            print("REPLACE ");
            printIdentifier(getColumnName(sourceColumn));
            if (newDefault != null)
            {
                writeColumnDefaultValueStmt(sourceTable, targetColumn);
            }
            else
            {
                print(" DEFAULT NULL");
            }
            printEndOfStatement();
        }
   }
}