/*
* Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
* Version 1.0, and under the Eclipse Public License, Version 1.0
* (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.command.ddl;
import java.util.ArrayList;
import java.util.HashSet;
import org.h2.command.CommandInterface;
import org.h2.constant.ErrorCode;
import org.h2.constraint.Constraint;
import org.h2.constraint.ConstraintCheck;
import org.h2.constraint.ConstraintReferential;
import org.h2.constraint.ConstraintUnique;
import org.h2.engine.Constants;
import org.h2.engine.Database;
import org.h2.engine.Right;
import org.h2.engine.Session;
import org.h2.expression.Expression;
import org.h2.index.Index;
import org.h2.index.IndexType;
import org.h2.message.DbException;
import org.h2.schema.Schema;
import org.h2.table.Column;
import org.h2.table.IndexColumn;
import org.h2.table.Table;
import org.h2.table.TableFilter;
import org.h2.util.New;
/**
* This class represents the statement
* ALTER TABLE ADD CONSTRAINT
*/
public class AlterTableAddConstraint extends SchemaCommand {
private int type;
private String constraintName;
private String tableName;
private IndexColumn[] indexColumns;
private int deleteAction;
private int updateAction;
private Schema refSchema;
private String refTableName;
private IndexColumn[] refIndexColumns;
private Expression checkExpression;
private Index index, refIndex;
private String comment;
private boolean checkExisting;
private boolean primaryKeyHash;
private boolean ifNotExists;
public AlterTableAddConstraint(Session session, Schema schema, boolean ifNotExists) {
super(session, schema);
this.ifNotExists = ifNotExists;
}
private String generateConstraintName(Table table) {
if (constraintName == null) {
constraintName = getSchema().getUniqueConstraintName(session, table);
}
return constraintName;
}
public int update() {
try {
return tryUpdate();
} finally {
getSchema().freeUniqueName(constraintName);
}
}
/**
* Try to execute the statement.
*
* @return the update count
*/
private int tryUpdate() {
if (!transactional) {
session.commit(true);
}
Database db = session.getDatabase();
Table table = getSchema().getTableOrView(session, tableName);
if (getSchema().findConstraint(session, constraintName) != null) {
if (ifNotExists) {
return 0;
}
throw DbException.get(ErrorCode.CONSTRAINT_ALREADY_EXISTS_1, constraintName);
}
session.getUser().checkRight(table, Right.ALL);
table.lock(session, true, true);
Constraint constraint;
switch (type) {
case CommandInterface.ALTER_TABLE_ADD_CONSTRAINT_PRIMARY_KEY: {
IndexColumn.mapColumns(indexColumns, table);
index = table.findPrimaryKey();
ArrayList<Constraint> constraints = table.getConstraints();
for (int i = 0; constraints != null && i < constraints.size(); i++) {
Constraint c = constraints.get(i);
if (Constraint.PRIMARY_KEY.equals(c.getConstraintType())) {
throw DbException.get(ErrorCode.SECOND_PRIMARY_KEY);
}
}
if (index != null) {
// if there is an index, it must match with the one declared
// we don't test ascending / descending
IndexColumn[] pkCols = index.getIndexColumns();
if (pkCols.length != indexColumns.length) {
throw DbException.get(ErrorCode.SECOND_PRIMARY_KEY);
}
for (int i = 0; i < pkCols.length; i++) {
if (pkCols[i].column != indexColumns[i].column) {
throw DbException.get(ErrorCode.SECOND_PRIMARY_KEY);
}
}
}
if (index == null) {
IndexType indexType = IndexType.createPrimaryKey(table.isPersistIndexes(), primaryKeyHash);
String indexName = table.getSchema().getUniqueIndexName(session, table, Constants.PREFIX_PRIMARY_KEY);
int id = getObjectId();
try {
index = table.addIndex(session, indexName, id, indexColumns, indexType, true, null);
} finally {
getSchema().freeUniqueName(indexName);
}
}
index.getIndexType().setBelongsToConstraint(true);
int constraintId = getObjectId();
String name = generateConstraintName(table);
ConstraintUnique pk = new ConstraintUnique(getSchema(), constraintId, name, table, true);
pk.setColumns(indexColumns);
pk.setIndex(index, true);
constraint = pk;
break;
}
case CommandInterface.ALTER_TABLE_ADD_CONSTRAINT_UNIQUE: {
IndexColumn.mapColumns(indexColumns, table);
boolean isOwner = false;
if (index != null && canUseUniqueIndex(index, table, indexColumns)) {
isOwner = true;
index.getIndexType().setBelongsToConstraint(true);
} else {
index = getUniqueIndex(table, indexColumns);
if (index == null) {
index = createIndex(table, indexColumns, true);
isOwner = true;
}
}
int id = getObjectId();
String name = generateConstraintName(table);
ConstraintUnique unique = new ConstraintUnique(getSchema(), id, name, table, false);
unique.setColumns(indexColumns);
unique.setIndex(index, isOwner);
constraint = unique;
break;
}
case CommandInterface.ALTER_TABLE_ADD_CONSTRAINT_CHECK: {
int id = getObjectId();
String name = generateConstraintName(table);
ConstraintCheck check = new ConstraintCheck(getSchema(), id, name, table);
TableFilter filter = new TableFilter(session, table, null, false, null);
checkExpression.mapColumns(filter, 0);
checkExpression = checkExpression.optimize(session);
check.setExpression(checkExpression);
check.setTableFilter(filter);
constraint = check;
if (checkExisting) {
check.checkExistingData(session);
}
break;
}
case CommandInterface.ALTER_TABLE_ADD_CONSTRAINT_REFERENTIAL: {
Table refTable = refSchema.getTableOrView(session, refTableName);
session.getUser().checkRight(refTable, Right.ALL);
if (!refTable.canReference()) {
throw DbException.get(ErrorCode.FEATURE_NOT_SUPPORTED_1, "Reference " + refTable.getSQL());
}
boolean isOwner = false;
IndexColumn.mapColumns(indexColumns, table);
if (index != null && canUseIndex(index, table, indexColumns)) {
isOwner = true;
index.getIndexType().setBelongsToConstraint(true);
} else {
index = getIndex(table, indexColumns);
if (index == null) {
index = createIndex(table, indexColumns, false);
isOwner = true;
}
}
if (refIndexColumns == null) {
Index refIdx = refTable.getPrimaryKey();
refIndexColumns = refIdx.getIndexColumns();
} else {
IndexColumn.mapColumns(refIndexColumns, refTable);
}
if (refIndexColumns.length != indexColumns.length) {
throw DbException.get(ErrorCode.COLUMN_COUNT_DOES_NOT_MATCH);
}
boolean isRefOwner = false;
if (refIndex != null && refIndex.getTable() == refTable) {
isRefOwner = true;
refIndex.getIndexType().setBelongsToConstraint(true);
} else {
refIndex = null;
}
if (refIndex == null) {
refIndex = getUniqueIndex(refTable, refIndexColumns);
if (refIndex == null) {
refIndex = createIndex(refTable, refIndexColumns, true);
isRefOwner = true;
}
}
int id = getObjectId();
String name = generateConstraintName(table);
ConstraintReferential ref = new ConstraintReferential(getSchema(), id, name, table);
ref.setColumns(indexColumns);
ref.setIndex(index, isOwner);
ref.setRefTable(refTable);
ref.setRefColumns(refIndexColumns);
ref.setRefIndex(refIndex, isRefOwner);
if (checkExisting) {
ref.checkExistingData(session);
}
constraint = ref;
refTable.addConstraint(constraint);
ref.setDeleteAction(deleteAction);
ref.setUpdateAction(updateAction);
break;
}
default:
throw DbException.throwInternalError("type=" + type);
}
// parent relationship is already set with addConstraint
constraint.setComment(comment);
if (table.isTemporary() && !table.isGlobalTemporary()) {
session.addLocalTempTableConstraint(constraint);
} else {
db.addSchemaObject(session, constraint);
}
table.addConstraint(constraint);
return 0;
}
private Index createIndex(Table t, IndexColumn[] cols, boolean unique) {
int indexId = getObjectId();
IndexType indexType;
if (unique) {
// for unique constraints
indexType = IndexType.createUnique(t.isPersistIndexes(), false);
} else {
// constraints
indexType = IndexType.createNonUnique(t.isPersistIndexes());
}
indexType.setBelongsToConstraint(true);
String prefix = constraintName == null ? "CONSTRAINT" : constraintName;
String indexName = t.getSchema().getUniqueIndexName(session, t, prefix + "_INDEX_");
try {
return t.addIndex(session, indexName, indexId, cols, indexType, true, null);
} finally {
getSchema().freeUniqueName(indexName);
}
}
public void setDeleteAction(int action) {
this.deleteAction = action;
}
public void setUpdateAction(int action) {
this.updateAction = action;
}
private static Index getUniqueIndex(Table t, IndexColumn[] cols) {
for (Index idx : t.getIndexes()) {
if (canUseUniqueIndex(idx, t, cols)) {
return idx;
}
}
return null;
}
private static Index getIndex(Table t, IndexColumn[] cols) {
for (Index idx : t.getIndexes()) {
if (canUseIndex(idx, t, cols)) {
return idx;
}
}
return null;
}
private static boolean canUseUniqueIndex(Index idx, Table table, IndexColumn[] cols) {
if (idx.getTable() != table || !idx.getIndexType().isUnique()) {
return false;
}
Column[] indexCols = idx.getColumns();
if (indexCols.length > cols.length) {
return false;
}
HashSet<Column> set = New.hashSet();
for (IndexColumn c : cols) {
set.add(c.column);
}
for (Column c : indexCols) {
// all columns of the index must be part of the list,
// but not all columns of the list need to be part of the index
if (!set.contains(c)) {
return false;
}
}
return true;
}
private static boolean canUseIndex(Index existingIndex, Table table, IndexColumn[] cols) {
if (existingIndex.getTable() != table || existingIndex.getCreateSQL() == null) {
// can't use the scan index or index of another table
return false;
}
Column[] indexCols = existingIndex.getColumns();
if (indexCols.length < cols.length) {
return false;
}
for (IndexColumn col : cols) {
// all columns of the list must be part of the index,
// but not all columns of the index need to be part of the list
// holes are not allowed (index=a,b,c & list=a,b is ok; but list=a,c
// is not)
int idx = existingIndex.getColumnIndex(col.column);
if (idx < 0 || idx >= cols.length) {
return false;
}
}
return true;
}
public void setConstraintName(String constraintName) {
this.constraintName = constraintName;
}
public void setType(int type) {
this.type = type;
}
public int getType() {
return type;
}
public void setCheckExpression(Expression expression) {
this.checkExpression = expression;
}
public void setTableName(String tableName) {
this.tableName = tableName;
}
public void setIndexColumns(IndexColumn[] indexColumns) {
this.indexColumns = indexColumns;
}
public IndexColumn[] getIndexColumns() {
return indexColumns;
}
/**
* Set the referenced table.
*
* @param refSchema the schema
* @param ref the table name
*/
public void setRefTableName(Schema refSchema, String ref) {
this.refSchema = refSchema;
this.refTableName = ref;
}
public void setRefIndexColumns(IndexColumn[] indexColumns) {
this.refIndexColumns = indexColumns;
}
public void setIndex(Index index) {
this.index = index;
}
public void setRefIndex(Index refIndex) {
this.refIndex = refIndex;
}
public void setComment(String comment) {
this.comment = comment;
}
public void setCheckExisting(boolean b) {
this.checkExisting = b;
}
public void setPrimaryKeyHash(boolean b) {
this.primaryKeyHash = b;
}
}