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org.h2.table.TableLink 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.table;
import java.sql.DatabaseMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Objects;
import org.h2.api.ErrorCode;
import org.h2.command.Prepared;
import org.h2.engine.Session;
import org.h2.engine.UndoLogRecord;
import org.h2.index.Index;
import org.h2.index.IndexType;
import org.h2.index.LinkedIndex;
import org.h2.message.DbException;
import org.h2.result.Row;
import org.h2.result.RowList;
import org.h2.schema.Schema;
import org.h2.util.StringUtils;
import org.h2.util.Utils;
import org.h2.value.DataType;
import org.h2.value.TypeInfo;
import org.h2.value.Value;
import org.h2.value.ValueDate;
import org.h2.value.ValueTime;
import org.h2.value.ValueTimestamp;
/**
* A linked table contains connection information for a table accessible by
* JDBC. The table may be stored in a different database.
*/
public class TableLink extends Table {
private static final int MAX_RETRY = 2;
private static final long ROW_COUNT_APPROXIMATION = 100_000;
private final String originalSchema;
private String driver, url, user, password, originalTable, qualifiedTableName;
private TableLinkConnection conn;
private HashMap preparedMap = new HashMap<>();
private final ArrayList indexes = Utils.newSmallArrayList();
private final boolean emitUpdates;
private LinkedIndex linkedIndex;
private DbException connectException;
private boolean storesLowerCase;
private boolean storesMixedCase;
private boolean storesMixedCaseQuoted;
private boolean supportsMixedCaseIdentifiers;
private boolean globalTemporary;
private boolean readOnly;
private boolean targetsMySql;
public TableLink(Schema schema, int id, String name, String driver,
String url, String user, String password, String originalSchema,
String originalTable, boolean emitUpdates, boolean force) {
super(schema, id, name, false, true);
this.driver = driver;
this.url = url;
this.user = user;
this.password = password;
this.originalSchema = originalSchema;
this.originalTable = originalTable;
this.emitUpdates = emitUpdates;
this.targetsMySql = isMySqlUrl(this.url);
try {
connect();
} catch (DbException e) {
if (!force) {
throw e;
}
Column[] cols = { };
setColumns(cols);
linkedIndex = new LinkedIndex(this, id, IndexColumn.wrap(cols),
IndexType.createNonUnique(false));
indexes.add(linkedIndex);
}
}
private void connect() {
connectException = null;
for (int retry = 0;; retry++) {
try {
conn = database.getLinkConnection(driver, url, user, password);
synchronized (conn) {
try {
readMetaData();
return;
} catch (Exception e) {
// could be SQLException or RuntimeException
conn.close(true);
conn = null;
throw DbException.convert(e);
}
}
} catch (DbException e) {
if (retry >= MAX_RETRY) {
connectException = e;
throw e;
}
}
}
}
private void readMetaData() throws SQLException {
DatabaseMetaData meta = conn.getConnection().getMetaData();
storesLowerCase = meta.storesLowerCaseIdentifiers();
storesMixedCase = meta.storesMixedCaseIdentifiers();
storesMixedCaseQuoted = meta.storesMixedCaseQuotedIdentifiers();
supportsMixedCaseIdentifiers = meta.supportsMixedCaseIdentifiers();
ArrayList columnList = Utils.newSmallArrayList();
HashMap columnMap = new HashMap<>();
String schema = null;
boolean isQuery = originalTable.startsWith("(");
if (!isQuery) {
try (ResultSet rs = meta.getTables(null, originalSchema, originalTable, null)) {
if (rs.next() && rs.next()) {
throw DbException.get(ErrorCode.SCHEMA_NAME_MUST_MATCH, originalTable);
}
}
try (ResultSet rs = meta.getColumns(null, originalSchema, originalTable, null)) {
int i = 0;
String catalog = null;
while (rs.next()) {
String thisCatalog = rs.getString("TABLE_CAT");
if (catalog == null) {
catalog = thisCatalog;
}
String thisSchema = rs.getString("TABLE_SCHEM");
if (schema == null) {
schema = thisSchema;
}
if (!Objects.equals(catalog, thisCatalog) ||
!Objects.equals(schema, thisSchema)) {
// if the table exists in multiple schemas or tables,
// use the alternative solution
columnMap.clear();
columnList.clear();
break;
}
String n = rs.getString("COLUMN_NAME");
n = convertColumnName(n);
int sqlType = rs.getInt("DATA_TYPE");
String sqlTypeName = rs.getString("TYPE_NAME");
long precision = rs.getInt("COLUMN_SIZE");
precision = convertPrecision(sqlType, precision);
int scale = rs.getInt("DECIMAL_DIGITS");
scale = convertScale(sqlType, scale);
int type = DataType.convertSQLTypeToValueType(sqlType, sqlTypeName);
Column col = new Column(n, TypeInfo.getTypeInfo(type, precision, scale, null));
col.setTable(this, i++);
columnList.add(col);
columnMap.put(n, col);
}
}
}
if (originalTable.indexOf('.') < 0 && !StringUtils.isNullOrEmpty(schema)) {
qualifiedTableName = schema + '.' + originalTable;
} else {
qualifiedTableName = originalTable;
}
// check if the table is accessible
try (Statement stat = conn.getConnection().createStatement();
ResultSet rs = stat.executeQuery("SELECT * FROM " + qualifiedTableName + " T WHERE 1=0")) {
if (columnList.isEmpty()) {
// alternative solution
ResultSetMetaData rsMeta = rs.getMetaData();
for (int i = 0; i < rsMeta.getColumnCount();) {
String n = rsMeta.getColumnName(i + 1);
n = convertColumnName(n);
int sqlType = rsMeta.getColumnType(i + 1);
long precision = rsMeta.getPrecision(i + 1);
precision = convertPrecision(sqlType, precision);
int scale = rsMeta.getScale(i + 1);
scale = convertScale(sqlType, scale);
int type = DataType.getValueTypeFromResultSet(rsMeta, i + 1);
Column col = new Column(n, TypeInfo.getTypeInfo(type, precision, scale, null));
col.setTable(this, i++);
columnList.add(col);
columnMap.put(n, col);
}
}
} catch (Exception e) {
throw DbException.get(ErrorCode.TABLE_OR_VIEW_NOT_FOUND_1, e,
originalTable + '(' + e.toString() + ')');
}
Column[] cols = columnList.toArray(new Column[0]);
setColumns(cols);
int id = getId();
linkedIndex = new LinkedIndex(this, id, IndexColumn.wrap(cols),
IndexType.createNonUnique(false));
indexes.add(linkedIndex);
if (!isQuery) {
readIndexes(meta, columnMap);
}
}
private void readIndexes(DatabaseMetaData meta, HashMap columnMap) {
String pkName = null;
try (ResultSet rs = meta.getPrimaryKeys(null, originalSchema, originalTable)) {
if (rs.next()) {
pkName = readPrimaryKey(rs, columnMap);
}
} catch (Exception e) {
// Some ODBC bridge drivers don't support it:
// some combinations of "DataDirect SequeLink(R) for JDBC"
// http://www.datadirect.com/index.ssp
}
try (ResultSet rs = meta.getIndexInfo(null, originalSchema, originalTable, false, true)) {
readIndexes(rs, columnMap, pkName);
} catch (Exception e) {
// Oracle throws an exception if the table is not found or is a
// SYNONYM
}
}
private String readPrimaryKey(ResultSet rs, HashMap columnMap) throws SQLException {
String pkName = null;
// the problem is, the rows are not sorted by KEY_SEQ
ArrayList list = Utils.newSmallArrayList();
do {
int idx = rs.getInt("KEY_SEQ");
if (StringUtils.isNullOrEmpty(pkName)) {
pkName = rs.getString("PK_NAME");
}
while (list.size() < idx) {
list.add(null);
}
String col = rs.getString("COLUMN_NAME");
col = convertColumnName(col);
Column column = columnMap.get(col);
if (idx == 0) {
// workaround for a bug in the SQLite JDBC driver
list.add(column);
} else {
list.set(idx - 1, column);
}
} while (rs.next());
addIndex(list, IndexType.createPrimaryKey(false, false));
return pkName;
}
private void readIndexes(ResultSet rs, HashMap columnMap, String pkName) throws SQLException {
String indexName = null;
ArrayList list = Utils.newSmallArrayList();
IndexType indexType = null;
while (rs.next()) {
if (rs.getShort("TYPE") == DatabaseMetaData.tableIndexStatistic) {
// ignore index statistics
continue;
}
String newIndex = rs.getString("INDEX_NAME");
if (pkName != null && pkName.equals(newIndex)) {
continue;
}
if (indexName != null && !indexName.equals(newIndex)) {
addIndex(list, indexType);
indexName = null;
}
if (indexName == null) {
indexName = newIndex;
list.clear();
}
boolean unique = !rs.getBoolean("NON_UNIQUE");
indexType = unique ? IndexType.createUnique(false, false) :
IndexType.createNonUnique(false);
String col = rs.getString("COLUMN_NAME");
col = convertColumnName(col);
Column column = columnMap.get(col);
list.add(column);
}
if (indexName != null) {
addIndex(list, indexType);
}
}
private static long convertPrecision(int sqlType, long precision) {
// workaround for an Oracle problem:
// for DATE columns, the reported precision is 7
// for DECIMAL columns, the reported precision is 0
switch (sqlType) {
case Types.DECIMAL:
case Types.NUMERIC:
if (precision == 0) {
precision = 65535;
}
break;
case Types.DATE:
precision = Math.max(ValueDate.PRECISION, precision);
break;
case Types.TIMESTAMP:
precision = Math.max(ValueTimestamp.MAXIMUM_PRECISION, precision);
break;
case Types.TIME:
precision = Math.max(ValueTime.MAXIMUM_PRECISION, precision);
break;
}
return precision;
}
private static int convertScale(int sqlType, int scale) {
// workaround for an Oracle problem:
// for DECIMAL columns, the reported precision is -127
switch (sqlType) {
case Types.DECIMAL:
case Types.NUMERIC:
if (scale < 0) {
scale = 32767;
}
break;
}
return scale;
}
private String convertColumnName(String columnName) {
if(targetsMySql) {
// MySQL column names are not case-sensitive on any platform
columnName = StringUtils.toUpperEnglish(columnName);
} else if ((storesMixedCase || storesLowerCase) &&
columnName.equals(StringUtils.toLowerEnglish(columnName))) {
columnName = StringUtils.toUpperEnglish(columnName);
} else if (storesMixedCase && !supportsMixedCaseIdentifiers) {
// TeraData
columnName = StringUtils.toUpperEnglish(columnName);
} else if (storesMixedCase && storesMixedCaseQuoted) {
// MS SQL Server (identifiers are case insensitive even if quoted)
columnName = StringUtils.toUpperEnglish(columnName);
}
return columnName;
}
private void addIndex(List list, IndexType indexType) {
// bind the index to the leading recognized columns in the index
// (null columns might come from a function-based index)
int firstNull = list.indexOf(null);
if (firstNull == 0) {
trace.info("Omitting linked index - no recognized columns.");
return;
} else if (firstNull > 0) {
trace.info("Unrecognized columns in linked index. " +
"Registering the index against the leading {0} " +
"recognized columns of {1} total columns.", firstNull, list.size());
list = list.subList(0, firstNull);
}
Column[] cols = list.toArray(new Column[0]);
Index index = new LinkedIndex(this, 0, IndexColumn.wrap(cols), indexType);
indexes.add(index);
}
@Override
public String getDropSQL() {
StringBuilder builder = new StringBuilder("DROP TABLE IF EXISTS ");
return getSQL(builder, true).toString();
}
@Override
public String getCreateSQL() {
StringBuilder buff = new StringBuilder("CREATE FORCE ");
if (isTemporary()) {
if (globalTemporary) {
buff.append("GLOBAL ");
} else {
buff.append("LOCAL ");
}
buff.append("TEMPORARY ");
}
buff.append("LINKED TABLE ");
getSQL(buff, true);
if (comment != null) {
buff.append(" COMMENT ");
StringUtils.quoteStringSQL(buff, comment);
}
buff.append('(');
StringUtils.quoteStringSQL(buff, driver).append(", ");
StringUtils.quoteStringSQL(buff, url).append(", ");
StringUtils.quoteStringSQL(buff, user).append(", ");
StringUtils.quoteStringSQL(buff, password).append(", ");
StringUtils.quoteStringSQL(buff, originalTable).append(')');
if (emitUpdates) {
buff.append(" EMIT UPDATES");
}
if (readOnly) {
buff.append(" READONLY");
}
buff.append(" /*").append(DbException.HIDE_SQL).append("*/");
return buff.toString();
}
@Override
public Index addIndex(Session session, String indexName, int indexId,
IndexColumn[] cols, IndexType indexType, boolean create,
String indexComment) {
throw DbException.getUnsupportedException("LINK");
}
@Override
public boolean lock(Session session, boolean exclusive, boolean forceLockEvenInMvcc) {
// nothing to do
return false;
}
@Override
public boolean isLockedExclusively() {
return false;
}
@Override
public Index getScanIndex(Session session) {
return linkedIndex;
}
private void checkReadOnly() {
if (readOnly) {
throw DbException.get(ErrorCode.DATABASE_IS_READ_ONLY);
}
}
@Override
public void removeRow(Session session, Row row) {
checkReadOnly();
getScanIndex(session).remove(session, row);
}
@Override
public void addRow(Session session, Row row) {
checkReadOnly();
getScanIndex(session).add(session, row);
}
@Override
public void close(Session session) {
if (conn != null) {
try {
conn.close(false);
} finally {
conn = null;
}
}
}
@Override
public synchronized long getRowCount(Session session) {
//The foo alias is used to support the PostgreSQL syntax
String sql = "SELECT COUNT(*) FROM " + qualifiedTableName + " as foo";
try {
PreparedStatement prep = execute(sql, null, false);
ResultSet rs = prep.getResultSet();
rs.next();
long count = rs.getLong(1);
rs.close();
reusePreparedStatement(prep, sql);
return count;
} catch (Exception e) {
throw wrapException(sql, e);
}
}
/**
* Wrap a SQL exception that occurred while accessing a linked table.
*
* @param sql the SQL statement
* @param ex the exception from the remote database
* @return the wrapped exception
*/
public static DbException wrapException(String sql, Exception ex) {
SQLException e = DbException.toSQLException(ex);
return DbException.get(ErrorCode.ERROR_ACCESSING_LINKED_TABLE_2,
e, sql, e.toString());
}
public String getQualifiedTable() {
return qualifiedTableName;
}
/**
* Execute a SQL statement using the given parameters. Prepared
* statements are kept in a hash map to avoid re-creating them.
*
* @param sql the SQL statement
* @param params the parameters or null
* @param reusePrepared if the prepared statement can be re-used immediately
* @return the prepared statement, or null if it is re-used
*/
public PreparedStatement execute(String sql, ArrayList params,
boolean reusePrepared) {
if (conn == null) {
throw connectException;
}
for (int retry = 0;; retry++) {
try {
synchronized (conn) {
PreparedStatement prep = preparedMap.remove(sql);
if (prep == null) {
prep = conn.getConnection().prepareStatement(sql);
}
if (trace.isDebugEnabled()) {
StringBuilder builder = new StringBuilder(getName()).append(":\n").append(sql);
if (params != null && !params.isEmpty()) {
builder.append(" {");
for (int i = 0, l = params.size(); i < l;) {
Value v = params.get(i);
if (i > 0) {
builder.append(", ");
}
builder.append(++i).append(": ");
v.getSQL(builder);
}
builder.append('}');
}
builder.append(';');
trace.debug(builder.toString());
}
if (params != null) {
for (int i = 0, size = params.size(); i < size; i++) {
Value v = params.get(i);
v.set(prep, i + 1);
}
}
prep.execute();
if (reusePrepared) {
reusePreparedStatement(prep, sql);
return null;
}
return prep;
}
} catch (SQLException e) {
if (retry >= MAX_RETRY) {
throw DbException.convert(e);
}
conn.close(true);
connect();
}
}
}
@Override
public void unlock(Session s) {
// nothing to do
}
@Override
public void checkRename() {
// ok
}
@Override
public void checkSupportAlter() {
throw DbException.getUnsupportedException("LINK");
}
@Override
public void truncate(Session session) {
throw DbException.getUnsupportedException("LINK");
}
@Override
public boolean canGetRowCount() {
return true;
}
@Override
public boolean canDrop() {
return true;
}
@Override
public TableType getTableType() {
return TableType.TABLE_LINK;
}
@Override
public void removeChildrenAndResources(Session session) {
super.removeChildrenAndResources(session);
close(session);
database.removeMeta(session, getId());
driver = null;
url = user = password = originalTable = null;
preparedMap = null;
invalidate();
}
public boolean isOracle() {
return url.startsWith("jdbc:oracle:");
}
private static boolean isMySqlUrl(String url) {
return url.startsWith("jdbc:mysql:")
|| url.startsWith("jdbc:mariadb:");
}
@Override
public ArrayList getIndexes() {
return indexes;
}
@Override
public long getMaxDataModificationId() {
// data may have been modified externally
return Long.MAX_VALUE;
}
@Override
public Index getUniqueIndex() {
for (Index idx : indexes) {
if (idx.getIndexType().isUnique()) {
return idx;
}
}
return null;
}
@Override
public void updateRows(Prepared prepared, Session session, RowList rows) {
boolean deleteInsert;
checkReadOnly();
if (emitUpdates) {
for (rows.reset(); rows.hasNext();) {
prepared.checkCanceled();
Row oldRow = rows.next();
Row newRow = rows.next();
linkedIndex.update(oldRow, newRow);
session.log(this, UndoLogRecord.DELETE, oldRow);
session.log(this, UndoLogRecord.INSERT, newRow);
}
deleteInsert = false;
} else {
deleteInsert = true;
}
if (deleteInsert) {
super.updateRows(prepared, session, rows);
}
}
public void setGlobalTemporary(boolean globalTemporary) {
this.globalTemporary = globalTemporary;
}
public void setReadOnly(boolean readOnly) {
this.readOnly = readOnly;
}
@Override
public long getRowCountApproximation() {
return ROW_COUNT_APPROXIMATION;
}
@Override
public long getDiskSpaceUsed() {
return 0;
}
/**
* Add this prepared statement to the list of cached statements.
*
* @param prep the prepared statement
* @param sql the SQL statement
*/
public void reusePreparedStatement(PreparedStatement prep, String sql) {
synchronized (conn) {
preparedMap.put(sql, prep);
}
}
@Override
public boolean isDeterministic() {
return false;
}
/**
* Linked tables don't know if they are readonly. This overwrites
* the default handling.
*/
@Override
public void checkWritingAllowed() {
// only the target database can verify this
}
/**
* Convert the values if required. Default values are not set (kept as
* null).
*
* @param session the session
* @param row the row
*/
@Override
public void validateConvertUpdateSequence(Session session, Row row) {
for (int i = 0; i < columns.length; i++) {
Value value = row.getValue(i);
if (value != null) {
// null means use the default value
Column column = columns[i];
Value v2 = column.validateConvertUpdateSequence(session, value);
if (v2 != value) {
row.setValue(i, v2);
}
}
}
}
/**
* Get or generate a default value for the given column. Default values are
* not set (kept as null).
*
* @param session the session
* @param column the column
* @return the value
*/
@Override
public Value getDefaultValue(Session session, Column column) {
return null;
}
}
