@Override
public int update() {
session.commit(true);
Database db = session.getDatabase();
session.getUser().checkRight(table, Right.ALL);
table.checkSupportAlter();
table.lock(session, true, true);
Sequence sequence = oldColumn == null ? null : oldColumn.getSequence();
if (newColumn != null) {
checkDefaultReferencesTable((Expression) newColumn.getDefaultExpression());
}
if (columnsToAdd != null) {
for (Column column : columnsToAdd) {
checkDefaultReferencesTable((Expression) column.getDefaultExpression());
}
}
switch (type) {
case CommandInterface.ALTER_TABLE_ALTER_COLUMN_NOT_NULL:
{
if (!oldColumn.isNullable()) {
// no change
break;
}
checkNoNullValues();
oldColumn.setNullable(false);
db.updateMeta(session, table);
break;
}
case CommandInterface.ALTER_TABLE_ALTER_COLUMN_NULL:
{
if (oldColumn.isNullable()) {
// no change
break;
}
checkNullable();
oldColumn.setNullable(true);
db.updateMeta(session, table);
break;
}
case CommandInterface.ALTER_TABLE_ALTER_COLUMN_DEFAULT:
{
checkDefaultReferencesTable(defaultExpression);
oldColumn.setSequence(null);
oldColumn.setDefaultExpression(session, defaultExpression);
removeSequence(sequence);
db.updateMeta(session, table);
break;
}
case CommandInterface.ALTER_TABLE_ALTER_COLUMN_CHANGE_TYPE:
{
// if the change is only increasing the precision, then we don't
// need to copy the table because the length is only a constraint,
// and does not affect the storage structure.
if (oldColumn.isWideningConversion(newColumn)) {
convertAutoIncrementColumn(newColumn);
oldColumn.copy(newColumn);
db.updateMeta(session, table);
} else {
oldColumn.setSequence(null);
oldColumn.setDefaultExpression(session, null);
oldColumn.setConvertNullToDefault(false);
if (oldColumn.isNullable() && !newColumn.isNullable()) {
checkNoNullValues();
} else if (!oldColumn.isNullable() && newColumn.isNullable()) {
checkNullable();
}
convertAutoIncrementColumn(newColumn);
copyData();
}
break;
}
case CommandInterface.ALTER_TABLE_ADD_COLUMN:
{
// ifNotExists only supported for single column add
if (ifNotExists
&& columnsToAdd.size() == 1
&& table.doesColumnExist(columnsToAdd.get(0).getName())) {
break;
}
for (Column column : columnsToAdd) {
if (column.isAutoIncrement()) {
int objId = getObjectId();
column.convertAutoIncrementToSequence(
session, getSchema(), objId, table.isTemporary());
}
}
copyData();
break;
}
case CommandInterface.ALTER_TABLE_DROP_COLUMN:
{
if (table.getColumns().length == 1) {
throw DbException.get(ErrorCode.CANNOT_DROP_LAST_COLUMN, oldColumn.getSQL());
}
table.dropSingleColumnConstraintsAndIndexes(session, oldColumn);
copyData();
break;
}
case CommandInterface.ALTER_TABLE_ALTER_COLUMN_SELECTIVITY:
{
int value = newSelectivity.optimize(session).getValue(session).getInt();
oldColumn.setSelectivity(value);
db.updateMeta(session, table);
break;
}
default:
DbException.throwInternalError("type=" + type);
}
return 0;
}
private Table cloneTableStructure(
Column[] columns, Database db, String tempName, ArrayList<Column> newColumns) {
for (Column col : columns) {
newColumns.add(col.getClone());
}
if (type == CommandInterface.ALTER_TABLE_DROP_COLUMN) {
int position = oldColumn.getColumnId();
newColumns.remove(position);
} else if (type == CommandInterface.ALTER_TABLE_ADD_COLUMN) {
int position;
if (addBefore != null) {
position = table.getColumn(addBefore).getColumnId();
} else if (addAfter != null) {
position = table.getColumn(addAfter).getColumnId() + 1;
} else {
position = columns.length;
}
for (Column column : columnsToAdd) {
newColumns.add(position++, column);
}
} else if (type == CommandInterface.ALTER_TABLE_ALTER_COLUMN_CHANGE_TYPE) {
int position = oldColumn.getColumnId();
newColumns.remove(position);
newColumns.add(position, newColumn);
}
// create a table object in order to get the SQL statement
// can't just use this table, because most column objects are 'shared'
// with the old table
// still need a new id because using 0 would mean: the new table tries
// to use the rows of the table 0 (the meta table)
int id = db.allocateObjectId();
CreateTableData data = new CreateTableData();
data.tableName = tempName;
data.id = id;
data.columns = newColumns;
data.temporary = table.isTemporary();
data.persistData = table.isPersistData();
data.persistIndexes = table.isPersistIndexes();
data.isHidden = table.isHidden();
data.create = true;
data.session = session;
data.storageEngineName = table.getStorageEngineName();
Table newTable = getSchema().createTable(data);
newTable.setComment(table.getComment());
StringBuilder buff = new StringBuilder();
buff.append(newTable.getCreateSQL());
if (table.supportsAlterColumnWithCopyData()) {
StringBuilder columnList = new StringBuilder();
for (Column nc : newColumns) {
if (columnList.length() > 0) {
columnList.append(", ");
}
if (type == CommandInterface.ALTER_TABLE_ADD_COLUMN && columnsToAdd.contains(nc)) {
Expression def = (Expression) nc.getDefaultExpression();
columnList.append(def == null ? "NULL" : def.getSQL());
} else {
columnList.append(nc.getSQL());
}
}
buff.append(" AS SELECT ");
if (columnList.length() == 0) {
// special case: insert into test select * from
buff.append('*');
} else {
buff.append(columnList);
}
buff.append(" FROM ").append(table.getSQL());
}
String newTableSQL = buff.toString();
String newTableName = newTable.getName();
Schema newTableSchema = newTable.getSchema();
newTable.removeChildrenAndResources(session);
execute(newTableSQL, true);
newTable = newTableSchema.getTableOrView(session, newTableName);
ArrayList<String> triggers = New.arrayList();
for (DbObject child : table.getChildren()) {
if (child instanceof Sequence) {
continue;
} else if (child instanceof Index) {
Index idx = (Index) child;
if (idx.getIndexType().getBelongsToConstraint()) {
continue;
}
}
String createSQL = child.getCreateSQL();
if (createSQL == null) {
continue;
}
if (child instanceof TableView) {
continue;
} else if (child.getType() == DbObject.TABLE_OR_VIEW) {
DbException.throwInternalError();
}
String quotedName = Parser.quoteIdentifier(tempName + "_" + child.getName());
String sql = null;
if (child instanceof ConstraintReferential) {
ConstraintReferential r = (ConstraintReferential) child;
if (r.getTable() != table) {
sql = r.getCreateSQLForCopy(r.getTable(), newTable, quotedName, false);
}
}
if (sql == null) {
sql = child.getCreateSQLForCopy(newTable, quotedName);
}
if (sql != null) {
if (child instanceof TriggerObject) {
triggers.add(sql);
} else {
execute(sql, true);
}
}
}
table.setModified();
// remove the sequences from the columns (except dropped columns)
// otherwise the sequence is dropped if the table is dropped
for (Column col : newColumns) {
Sequence seq = col.getSequence();
if (seq != null) {
table.removeSequence(seq);
col.setSequence(null);
}
}
for (String sql : triggers) {
execute(sql, true);
}
return newTable;
}