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org.h2.command.dml.Update Maven / Gradle / Ivy
/*
* Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (http://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.command.dml;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Objects;
import org.h2.api.ErrorCode;
import org.h2.api.Trigger;
import org.h2.command.CommandInterface;
import org.h2.command.Prepared;
import org.h2.engine.Right;
import org.h2.engine.Session;
import org.h2.expression.Expression;
import org.h2.expression.Parameter;
import org.h2.expression.ValueExpression;
import org.h2.message.DbException;
import org.h2.result.ResultInterface;
import org.h2.result.Row;
import org.h2.result.RowList;
import org.h2.table.Column;
import org.h2.table.PlanItem;
import org.h2.table.Table;
import org.h2.table.TableFilter;
import org.h2.util.Utils;
import org.h2.value.Value;
import org.h2.value.ValueNull;
/**
* This class represents the statement
* UPDATE
*/
public class Update extends Prepared {
private Expression condition;
private TableFilter targetTableFilter;// target of update
/**
* This table filter is for MERGE..USING support - not used in stand-alone DML
*/
private TableFilter sourceTableFilter;
/** The limit expression as specified in the LIMIT clause. */
private Expression limitExpr;
private boolean updateToCurrentValuesReturnsZero;
private final ArrayList columns = Utils.newSmallArrayList();
private final HashMap expressionMap = new HashMap<>();
private HashSet updatedKeysCollector;
public Update(Session session) {
super(session);
}
public void setTableFilter(TableFilter tableFilter) {
this.targetTableFilter = tableFilter;
}
public void setCondition(Expression condition) {
this.condition = condition;
}
public Expression getCondition( ) {
return this.condition;
}
/**
* Add an assignment of the form column = expression.
*
* @param column the column
* @param expression the expression
*/
public void setAssignment(Column column, Expression expression) {
if (expressionMap.containsKey(column)) {
throw DbException.get(ErrorCode.DUPLICATE_COLUMN_NAME_1, column
.getName());
}
columns.add(column);
expressionMap.put(column, expression);
if (expression instanceof Parameter) {
Parameter p = (Parameter) expression;
p.setColumn(column);
}
}
/**
* Sets the collector of updated keys.
*
* @param updatedKeysCollector the collector of updated keys
*/
public void setUpdatedKeysCollector(HashSet updatedKeysCollector) {
this.updatedKeysCollector = updatedKeysCollector;
}
@Override
public int update() {
targetTableFilter.startQuery(session);
targetTableFilter.reset();
try (RowList rows = new RowList(session)) {
Table table = targetTableFilter.getTable();
session.getUser().checkRight(table, Right.UPDATE);
table.fire(session, Trigger.UPDATE, true);
table.lock(session, true, false);
int columnCount = table.getColumns().length;
// get the old rows, compute the new rows
setCurrentRowNumber(0);
int count = 0;
Column[] columns = table.getColumns();
int limitRows = -1;
if (limitExpr != null) {
Value v = limitExpr.getValue(session);
if (v != ValueNull.INSTANCE) {
limitRows = v.getInt();
}
}
while (targetTableFilter.next()) {
setCurrentRowNumber(count+1);
if (limitRows >= 0 && count >= limitRows) {
break;
}
if (condition == null || condition.getBooleanValue(session)) {
Row oldRow = targetTableFilter.get();
if (table.isMVStore()) {
Row lockedRow = table.lockRow(session, oldRow);
if (lockedRow == null) {
continue;
}
if (!oldRow.hasSharedData(lockedRow)) {
oldRow = lockedRow;
targetTableFilter.set(oldRow);
if (condition != null && !condition.getBooleanValue(session)) {
continue;
}
}
}
Row newRow = table.getTemplateRow();
boolean setOnUpdate = false;
for (int i = 0; i < columnCount; i++) {
Expression newExpr = expressionMap.get(columns[i]);
Column column = table.getColumn(i);
Value newValue;
if (newExpr == null) {
if (column.getOnUpdateExpression() != null) {
setOnUpdate = true;
}
newValue = oldRow.getValue(i);
} else if (newExpr == ValueExpression.getDefault()) {
newValue = table.getDefaultValue(session, column);
} else {
newValue = column.convert(newExpr.getValue(session), session.getDatabase().getMode());
}
newRow.setValue(i, newValue);
}
long key = oldRow.getKey();
newRow.setKey(key);
if (setOnUpdate || updateToCurrentValuesReturnsZero) {
setOnUpdate = false;
for (int i = 0; i < columnCount; i++) {
// Use equals here to detect changes from numeric 0 to 0.0 and similar
if (!Objects.equals(oldRow.getValue(i), newRow.getValue(i))) {
setOnUpdate = true;
break;
}
}
if (setOnUpdate) {
for (int i = 0; i < columnCount; i++) {
if (expressionMap.get(columns[i]) == null) {
Column column = table.getColumn(i);
if (column.getOnUpdateExpression() != null) {
newRow.setValue(i, table.getOnUpdateValue(session, column));
}
}
}
} else if (updateToCurrentValuesReturnsZero) {
count--;
}
}
table.validateConvertUpdateSequence(session, newRow);
if (!table.fireRow() || !table.fireBeforeRow(session, oldRow, newRow)) {
rows.add(oldRow);
rows.add(newRow);
if (updatedKeysCollector != null) {
updatedKeysCollector.add(key);
}
}
count++;
}
}
// TODO self referencing referential integrity constraints
// don't work if update is multi-row and 'inversed' the condition!
// probably need multi-row triggers with 'deleted' and 'inserted'
// at the same time. anyway good for sql compatibility
// TODO update in-place (but if the key changes,
// we need to update all indexes) before row triggers
// the cached row is already updated - we need the old values
table.updateRows(this, session, rows);
if (table.fireRow()) {
for (rows.reset(); rows.hasNext();) {
Row o = rows.next();
Row n = rows.next();
table.fireAfterRow(session, o, n, false);
}
}
table.fire(session, Trigger.UPDATE, false);
return count;
}
}
@Override
public String getPlanSQL(boolean alwaysQuote) {
StringBuilder builder = new StringBuilder("UPDATE ");
targetTableFilter.getPlanSQL(builder, false, alwaysQuote).append("\nSET\n ");
for (int i = 0, size = columns.size(); i < size; i++) {
if (i > 0) {
builder.append(",\n ");
}
Column c = columns.get(i);
c.getSQL(builder, alwaysQuote).append(" = ");
expressionMap.get(c).getSQL(builder, alwaysQuote);
}
if (condition != null) {
builder.append("\nWHERE ");
condition.getUnenclosedSQL(builder, alwaysQuote);
}
if (limitExpr != null) {
builder.append("\nLIMIT ");
limitExpr.getUnenclosedSQL(builder, alwaysQuote);
}
return builder.toString();
}
@Override
public void prepare() {
if (condition != null) {
condition.mapColumns(targetTableFilter, 0, Expression.MAP_INITIAL);
condition = condition.optimize(session);
condition.createIndexConditions(session, targetTableFilter);
}
for (Column c : columns) {
Expression e = expressionMap.get(c);
e.mapColumns(targetTableFilter, 0, Expression.MAP_INITIAL);
if (sourceTableFilter!=null){
e.mapColumns(sourceTableFilter, 0, Expression.MAP_INITIAL);
}
expressionMap.put(c, e.optimize(session));
}
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.UPDATE;
}
public void setLimit(Expression limit) {
this.limitExpr = limit;
}
@Override
public boolean isCacheable() {
return true;
}
public TableFilter getSourceTableFilter() {
return sourceTableFilter;
}
public void setSourceTableFilter(TableFilter sourceTableFilter) {
this.sourceTableFilter = sourceTableFilter;
}
/**
* Sets expected update count for update to current values case.
*
* @param updateToCurrentValuesReturnsZero if zero should be returned as update
* count if update set row to current values
*/
public void setUpdateToCurrentValuesReturnsZero(boolean updateToCurrentValuesReturnsZero) {
this.updateToCurrentValuesReturnsZero = updateToCurrentValuesReturnsZero;
}
}
