/**
* Check that this column is not referenced by a multi-column constraint or multi-column index. If
* it is, an exception is thrown. Single-column references and indexes are dropped.
*
* @param session the session
* @param col the column
* @throws DbException if the column is referenced by multi-column constraints or indexes
*/
public void dropSingleColumnConstraintsAndIndexes(Session session, Column col) {
ArrayList<Constraint> constraintsToDrop = New.arrayList();
if (constraints != null) {
for (int i = 0, size = constraints.size(); i < size; i++) {
Constraint constraint = constraints.get(i);
HashSet<Column> columns = constraint.getReferencedColumns(this);
if (!columns.contains(col)) {
continue;
}
if (columns.size() == 1) {
constraintsToDrop.add(constraint);
} else {
throw DbException.get(ErrorCode.COLUMN_IS_REFERENCED_1, constraint.getSQL());
}
}
}
ArrayList<Index> indexesToDrop = New.arrayList();
ArrayList<Index> indexes = getIndexes();
if (indexes != null) {
for (int i = 0, size = indexes.size(); i < size; i++) {
Index index = indexes.get(i);
if (index.getCreateSQL() == null) {
continue;
}
if (index.getColumnIndex(col) < 0) {
continue;
}
if (index.getColumns().length == 1) {
indexesToDrop.add(index);
} else {
throw DbException.get(ErrorCode.COLUMN_IS_REFERENCED_1, index.getSQL());
}
}
}
for (Constraint c : constraintsToDrop) {
session.getDatabase().removeSchemaObject(session, c);
}
for (Index i : indexesToDrop) {
// the index may already have been dropped when dropping the constraint
if (getIndexes().contains(i)) {
session.getDatabase().removeSchemaObject(session, i);
}
}
}
