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/*
* Copyright 2004-2018 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.index;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.HashSet;
import org.h2.engine.Constants;
import org.h2.engine.Session;
import org.h2.message.DbException;
import org.h2.result.Row;
import org.h2.result.SearchRow;
import org.h2.result.SortOrder;
import org.h2.table.Column;
import org.h2.table.IndexColumn;
import org.h2.table.TableFilter;
import org.h2.table.TableLink;
import org.h2.util.New;
import org.h2.util.StatementBuilder;
import org.h2.value.Value;
import org.h2.value.ValueNull;
/**
* A linked index is a index for a linked (remote) table.
* It is backed by an index on the remote table which is accessed over JDBC.
*/
public class LinkedIndex extends BaseIndex {
private final TableLink link;
private final String targetTableName;
private long rowCount;
public LinkedIndex(TableLink table, int id, IndexColumn[] columns,
IndexType indexType) {
initBaseIndex(table, id, null, columns, indexType);
link = table;
targetTableName = link.getQualifiedTable();
}
@Override
public String getCreateSQL() {
return null;
}
@Override
public void close(Session session) {
// nothing to do
}
private static boolean isNull(Value v) {
return v == null || v == ValueNull.INSTANCE;
}
@Override
public void add(Session session, Row row) {
ArrayList params = New.arrayList();
StatementBuilder buff = new StatementBuilder("INSERT INTO ");
buff.append(targetTableName).append(" VALUES(");
for (int i = 0; i < row.getColumnCount(); i++) {
Value v = row.getValue(i);
buff.appendExceptFirst(", ");
if (v == null) {
buff.append("DEFAULT");
} else if (isNull(v)) {
buff.append("NULL");
} else {
buff.append('?');
params.add(v);
}
}
buff.append(')');
String sql = buff.toString();
try {
link.execute(sql, params, true);
rowCount++;
} catch (Exception e) {
throw TableLink.wrapException(sql, e);
}
}
@Override
public Cursor find(Session session, SearchRow first, SearchRow last) {
ArrayList params = New.arrayList();
StatementBuilder buff = new StatementBuilder("SELECT * FROM ");
buff.append(targetTableName).append(" T");
for (int i = 0; first != null && i < first.getColumnCount(); i++) {
Value v = first.getValue(i);
if (v != null) {
buff.appendOnlyFirst(" WHERE ");
buff.appendExceptFirst(" AND ");
Column col = table.getColumn(i);
buff.append(col.getSQL());
if (v == ValueNull.INSTANCE) {
buff.append(" IS NULL");
} else {
buff.append(">=");
addParameter(buff, col);
params.add(v);
}
}
}
for (int i = 0; last != null && i < last.getColumnCount(); i++) {
Value v = last.getValue(i);
if (v != null) {
buff.appendOnlyFirst(" WHERE ");
buff.appendExceptFirst(" AND ");
Column col = table.getColumn(i);
buff.append(col.getSQL());
if (v == ValueNull.INSTANCE) {
buff.append(" IS NULL");
} else {
buff.append("<=");
addParameter(buff, col);
params.add(v);
}
}
}
String sql = buff.toString();
try {
PreparedStatement prep = link.execute(sql, params, false);
ResultSet rs = prep.getResultSet();
return new LinkedCursor(link, rs, session, sql, prep);
} catch (Exception e) {
throw TableLink.wrapException(sql, e);
}
}
private void addParameter(StatementBuilder buff, Column col) {
if (col.getType() == Value.STRING_FIXED && link.isOracle()) {
// workaround for Oracle
// create table test(id int primary key, name char(15));
// insert into test values(1, 'Hello')
// select * from test where name = ? -- where ? = "Hello" > no rows
buff.append("CAST(? AS CHAR(").append(col.getPrecision()).append("))");
} else {
buff.append('?');
}
}
@Override
public double getCost(Session session, int[] masks,
TableFilter[] filters, int filter, SortOrder sortOrder,
HashSet allColumnsSet) {
return 100 + getCostRangeIndex(masks, rowCount +
Constants.COST_ROW_OFFSET, filters, filter, sortOrder, false, allColumnsSet);
}
@Override
public void remove(Session session) {
// nothing to do
}
@Override
public void truncate(Session session) {
// nothing to do
}
@Override
public void checkRename() {
throw DbException.getUnsupportedException("LINKED");
}
@Override
public boolean needRebuild() {
return false;
}
@Override
public boolean canGetFirstOrLast() {
return false;
}
@Override
public Cursor findFirstOrLast(Session session, boolean first) {
// TODO optimization: could get the first or last value (in any case;
// maybe not optimized)
throw DbException.getUnsupportedException("LINKED");
}
@Override
public void remove(Session session, Row row) {
ArrayList params = New.arrayList();
StatementBuilder buff = new StatementBuilder("DELETE FROM ");
buff.append(targetTableName).append(" WHERE ");
for (int i = 0; i < row.getColumnCount(); i++) {
buff.appendExceptFirst("AND ");
Column col = table.getColumn(i);
buff.append(col.getSQL());
Value v = row.getValue(i);
if (isNull(v)) {
buff.append(" IS NULL ");
} else {
buff.append('=');
addParameter(buff, col);
params.add(v);
buff.append(' ');
}
}
String sql = buff.toString();
try {
PreparedStatement prep = link.execute(sql, params, false);
int count = prep.executeUpdate();
link.reusePreparedStatement(prep, sql);
rowCount -= count;
} catch (Exception e) {
throw TableLink.wrapException(sql, e);
}
}
/**
* Update a row using a UPDATE statement. This method is to be called if the
* emit updates option is enabled.
*
* @param oldRow the old data
* @param newRow the new data
*/
public void update(Row oldRow, Row newRow) {
ArrayList params = New.arrayList();
StatementBuilder buff = new StatementBuilder("UPDATE ");
buff.append(targetTableName).append(" SET ");
for (int i = 0; i < newRow.getColumnCount(); i++) {
buff.appendExceptFirst(", ");
buff.append(table.getColumn(i).getSQL()).append('=');
Value v = newRow.getValue(i);
if (v == null) {
buff.append("DEFAULT");
} else {
buff.append('?');
params.add(v);
}
}
buff.append(" WHERE ");
buff.resetCount();
for (int i = 0; i < oldRow.getColumnCount(); i++) {
Column col = table.getColumn(i);
buff.appendExceptFirst(" AND ");
buff.append(col.getSQL());
Value v = oldRow.getValue(i);
if (isNull(v)) {
buff.append(" IS NULL");
} else {
buff.append('=');
params.add(v);
addParameter(buff, col);
}
}
String sql = buff.toString();
try {
link.execute(sql, params, true);
} catch (Exception e) {
throw TableLink.wrapException(sql, e);
}
}
@Override
public long getRowCount(Session session) {
return rowCount;
}
@Override
public long getRowCountApproximation() {
return rowCount;
}
@Override
public long getDiskSpaceUsed() {
return 0;
}
}
