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org.h2.command.dml.Delete Maven / Gradle / Ivy
/*
* Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.command.dml;
import java.util.HashSet;
import org.h2.api.Trigger;
import org.h2.command.CommandInterface;
import org.h2.command.Prepared;
import org.h2.engine.DbObject;
import org.h2.engine.Right;
import org.h2.engine.Session;
import org.h2.engine.UndoLogRecord;
import org.h2.expression.Expression;
import org.h2.expression.ExpressionVisitor;
import org.h2.result.ResultInterface;
import org.h2.result.ResultTarget;
import org.h2.result.Row;
import org.h2.result.RowList;
import org.h2.table.DataChangeDeltaTable.ResultOption;
import org.h2.table.PlanItem;
import org.h2.table.Table;
import org.h2.table.TableFilter;
import org.h2.value.Value;
import org.h2.value.ValueNull;
/**
* This class represents the statement
* DELETE
*/
public class Delete extends Prepared implements DataChangeStatement {
private Expression condition;
private TableFilter targetTableFilter;
/**
* The limit expression as specified in the LIMIT or TOP clause.
*/
private Expression limitExpr;
/**
* This table filter is for MERGE..USING support - not used in stand-alone DML
*/
private TableFilter sourceTableFilter;
private HashSet keysFilter;
private ResultTarget deltaChangeCollector;
private ResultOption deltaChangeCollectionMode;
public Delete(Session session) {
super(session);
}
@Override
public Table getTable() {
return targetTableFilter.getTable();
}
public void setTableFilter(TableFilter tableFilter) {
this.targetTableFilter = tableFilter;
}
public void setCondition(Expression condition) {
this.condition = condition;
}
public Expression getCondition() {
return this.condition;
}
/**
* Sets the keys filter.
*
* @param keysFilter the keys filter
*/
public void setKeysFilter(HashSet keysFilter) {
this.keysFilter = keysFilter;
}
@Override
public void setDeltaChangeCollector(ResultTarget deltaChangeCollector, ResultOption deltaChangeCollectionMode) {
this.deltaChangeCollector = deltaChangeCollector;
this.deltaChangeCollectionMode = deltaChangeCollectionMode;
}
@Override
public int update() {
targetTableFilter.startQuery(session);
targetTableFilter.reset();
Table table = targetTableFilter.getTable();
session.getUser().checkRight(table, Right.DELETE);
table.fire(session, Trigger.DELETE, true);
table.lock(session, true, false);
int limitRows = -1;
if (limitExpr != null) {
Value v = limitExpr.getValue(session);
if (v != ValueNull.INSTANCE) {
limitRows = v.getInt();
}
}
try (RowList rows = new RowList(session)) {
setCurrentRowNumber(0);
int count = 0;
while (limitRows != 0 && targetTableFilter.next()) {
setCurrentRowNumber(rows.size() + 1);
if (condition == null || condition.getBooleanValue(session)
// the following is to support Oracle-style MERGE
|| (keysFilter != null && table.isMVStore())) {
Row row = targetTableFilter.get();
if (keysFilter == null || keysFilter.contains(row.getKey())) {
if (table.isMVStore()) {
Row lockedRow = table.lockRow(session, row);
if (lockedRow == null) {
continue;
}
if (!row.hasSharedData(lockedRow)) {
row = lockedRow;
targetTableFilter.set(row);
if (condition != null && !condition.getBooleanValue(session)) {
continue;
}
}
}
if (deltaChangeCollectionMode == ResultOption.OLD) {
deltaChangeCollector.addRow(row.getValueList());
}
if (!table.fireRow() || !table.fireBeforeRow(session, row, null)) {
rows.add(row);
}
count++;
if (limitRows >= 0 && count >= limitRows) {
break;
}
}
}
}
int rowScanCount = 0;
for (rows.reset(); rows.hasNext();) {
if ((++rowScanCount & 127) == 0) {
checkCanceled();
}
Row row = rows.next();
table.removeRow(session, row);
session.log(table, UndoLogRecord.DELETE, row);
}
if (table.fireRow()) {
for (rows.reset(); rows.hasNext();) {
Row row = rows.next();
table.fireAfterRow(session, row, null, false);
}
}
table.fire(session, Trigger.DELETE, false);
return count;
}
}
@Override
public String getPlanSQL(boolean alwaysQuote) {
StringBuilder buff = new StringBuilder();
buff.append("DELETE FROM ");
targetTableFilter.getPlanSQL(buff, false, alwaysQuote);
if (condition != null) {
buff.append("\nWHERE ");
condition.getUnenclosedSQL(buff, alwaysQuote);
}
if (limitExpr != null) {
buff.append("\nLIMIT (");
limitExpr.getUnenclosedSQL(buff, alwaysQuote).append(')');
}
return buff.toString();
}
@Override
public void prepare() {
if (condition != null) {
condition.mapColumns(targetTableFilter, 0, Expression.MAP_INITIAL);
if (sourceTableFilter != null) {
condition.mapColumns(sourceTableFilter, 0, Expression.MAP_INITIAL);
}
condition = condition.optimize(session);
condition.createIndexConditions(session, targetTableFilter);
}
TableFilter[] filters;
if (sourceTableFilter == null) {
filters = new TableFilter[] { targetTableFilter };
} else {
filters = new TableFilter[] { targetTableFilter, sourceTableFilter };
}
PlanItem item = targetTableFilter.getBestPlanItem(session, filters, 0,
new AllColumnsForPlan(filters));
targetTableFilter.setPlanItem(item);
targetTableFilter.prepare();
}
@Override
public boolean isTransactional() {
return true;
}
@Override
public ResultInterface queryMeta() {
return null;
}
@Override
public int getType() {
return CommandInterface.DELETE;
}
@Override
public String getStatementName() {
return "DELETE";
}
public void setLimit(Expression limit) {
this.limitExpr = limit;
}
@Override
public boolean isCacheable() {
return true;
}
public void setSourceTableFilter(TableFilter sourceTableFilter) {
this.sourceTableFilter = sourceTableFilter;
}
public TableFilter getTableFilter() {
return targetTableFilter;
}
public TableFilter getSourceTableFilter() {
return sourceTableFilter;
}
@Override
public void collectDependencies(HashSet dependencies) {
ExpressionVisitor visitor = ExpressionVisitor.getDependenciesVisitor(dependencies);
if (condition != null) {
condition.isEverything(visitor);
}
if (sourceTableFilter != null) {
Select select = sourceTableFilter.getSelect();
if (select != null) {
select.isEverything(visitor);
}
}
}
}
