org.hibernate.dialect.HSQLDialect Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.dialect;
import java.io.Serializable;
import java.sql.SQLException;
import java.sql.Types;
import org.hibernate.JDBCException;
import org.hibernate.LockMode;
import org.hibernate.StaleObjectStateException;
import org.hibernate.cfg.Environment;
import org.hibernate.dialect.function.AvgWithArgumentCastFunction;
import org.hibernate.dialect.function.NoArgSQLFunction;
import org.hibernate.dialect.function.SQLFunctionTemplate;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.dialect.function.VarArgsSQLFunction;
import org.hibernate.dialect.lock.LockingStrategy;
import org.hibernate.dialect.lock.OptimisticForceIncrementLockingStrategy;
import org.hibernate.dialect.lock.OptimisticLockingStrategy;
import org.hibernate.dialect.lock.PessimisticForceIncrementLockingStrategy;
import org.hibernate.dialect.lock.PessimisticReadSelectLockingStrategy;
import org.hibernate.dialect.lock.PessimisticWriteSelectLockingStrategy;
import org.hibernate.dialect.lock.SelectLockingStrategy;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.exception.spi.TemplatedViolatedConstraintNameExtracter;
import org.hibernate.exception.spi.ViolatedConstraintNameExtracter;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.internal.util.JdbcExceptionHelper;
import org.hibernate.internal.util.ReflectHelper;
import org.hibernate.persister.entity.Lockable;
import org.hibernate.type.StandardBasicTypes;
import org.jboss.logging.Logger;
/**
* An SQL dialect compatible with HSQLDB (HyperSQL).
*
* Note this version supports HSQLDB version 1.8 and higher, only.
*
* Enhancements to version 3.5.0 GA to provide basic support for both HSQLDB 1.8.x and 2.x
* Does not works with Hibernate 3.2 - 3.4 without alteration.
*
* @author Christoph Sturm
* @author Phillip Baird
* @author Fred Toussi
*/
public class HSQLDialect extends Dialect {
private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class, HSQLDialect.class.getName());
/**
* version is 18 for 1.8 or 20 for 2.0
*/
private int hsqldbVersion = 18;
public HSQLDialect() {
super();
try {
Class props = ReflectHelper.classForName( "org.hsqldb.persist.HsqlDatabaseProperties" );
String versionString = (String) props.getDeclaredField( "THIS_VERSION" ).get( null );
hsqldbVersion = Integer.parseInt( versionString.substring( 0, 1 ) ) * 10;
hsqldbVersion += Integer.parseInt( versionString.substring( 2, 3 ) );
}
catch ( Throwable e ) {
// must be a very old version
}
registerColumnType( Types.BIGINT, "bigint" );
registerColumnType( Types.BINARY, "binary($l)" );
registerColumnType( Types.BIT, "bit" );
registerColumnType( Types.BOOLEAN, "boolean" );
registerColumnType( Types.CHAR, "char($l)" );
registerColumnType( Types.DATE, "date" );
registerColumnType( Types.DECIMAL, "decimal($p,$s)" );
registerColumnType( Types.DOUBLE, "double" );
registerColumnType( Types.FLOAT, "float" );
registerColumnType( Types.INTEGER, "integer" );
registerColumnType( Types.LONGVARBINARY, "longvarbinary" );
registerColumnType( Types.LONGVARCHAR, "longvarchar" );
registerColumnType( Types.SMALLINT, "smallint" );
registerColumnType( Types.TINYINT, "tinyint" );
registerColumnType( Types.TIME, "time" );
registerColumnType( Types.TIMESTAMP, "timestamp" );
registerColumnType( Types.VARCHAR, "varchar($l)" );
registerColumnType( Types.VARBINARY, "varbinary($l)" );
if ( hsqldbVersion < 20 ) {
registerColumnType( Types.NUMERIC, "numeric" );
}
else {
registerColumnType( Types.NUMERIC, "numeric($p,$s)" );
}
//HSQL has no Blob/Clob support .... but just put these here for now!
if ( hsqldbVersion < 20 ) {
registerColumnType( Types.BLOB, "longvarbinary" );
registerColumnType( Types.CLOB, "longvarchar" );
}
else {
registerColumnType( Types.BLOB, "blob($l)" );
registerColumnType( Types.CLOB, "clob($l)" );
}
// aggregate functions
registerFunction( "avg", new AvgWithArgumentCastFunction( "double" ) );
// string functions
registerFunction( "ascii", new StandardSQLFunction( "ascii", StandardBasicTypes.INTEGER ) );
registerFunction( "char", new StandardSQLFunction( "char", StandardBasicTypes.CHARACTER ) );
registerFunction( "lower", new StandardSQLFunction( "lower" ) );
registerFunction( "upper", new StandardSQLFunction( "upper" ) );
registerFunction( "lcase", new StandardSQLFunction( "lcase" ) );
registerFunction( "ucase", new StandardSQLFunction( "ucase" ) );
registerFunction( "soundex", new StandardSQLFunction( "soundex", StandardBasicTypes.STRING ) );
registerFunction( "ltrim", new StandardSQLFunction( "ltrim" ) );
registerFunction( "rtrim", new StandardSQLFunction( "rtrim" ) );
registerFunction( "reverse", new StandardSQLFunction( "reverse" ) );
registerFunction( "space", new StandardSQLFunction( "space", StandardBasicTypes.STRING ) );
registerFunction( "str", new SQLFunctionTemplate( StandardBasicTypes.STRING, "cast(?1 as varchar(256))" ) );
registerFunction( "to_char", new StandardSQLFunction( "to_char", StandardBasicTypes.STRING ) );
registerFunction( "rawtohex", new StandardSQLFunction( "rawtohex" ) );
registerFunction( "hextoraw", new StandardSQLFunction( "hextoraw" ) );
// system functions
registerFunction( "user", new NoArgSQLFunction( "user", StandardBasicTypes.STRING ) );
registerFunction( "database", new NoArgSQLFunction( "database", StandardBasicTypes.STRING ) );
// datetime functions
if ( hsqldbVersion < 20 ) {
registerFunction( "sysdate", new NoArgSQLFunction( "sysdate", StandardBasicTypes.DATE, false ) );
} else {
registerFunction( "sysdate", new NoArgSQLFunction( "sysdate", StandardBasicTypes.TIMESTAMP, false ) );
}
registerFunction( "current_date", new NoArgSQLFunction( "current_date", StandardBasicTypes.DATE, false ) );
registerFunction( "curdate", new NoArgSQLFunction( "curdate", StandardBasicTypes.DATE ) );
registerFunction(
"current_timestamp", new NoArgSQLFunction( "current_timestamp", StandardBasicTypes.TIMESTAMP, false )
);
registerFunction( "now", new NoArgSQLFunction( "now", StandardBasicTypes.TIMESTAMP ) );
registerFunction( "current_time", new NoArgSQLFunction( "current_time", StandardBasicTypes.TIME, false ) );
registerFunction( "curtime", new NoArgSQLFunction( "curtime", StandardBasicTypes.TIME ) );
registerFunction( "day", new StandardSQLFunction( "day", StandardBasicTypes.INTEGER ) );
registerFunction( "dayofweek", new StandardSQLFunction( "dayofweek", StandardBasicTypes.INTEGER ) );
registerFunction( "dayofyear", new StandardSQLFunction( "dayofyear", StandardBasicTypes.INTEGER ) );
registerFunction( "dayofmonth", new StandardSQLFunction( "dayofmonth", StandardBasicTypes.INTEGER ) );
registerFunction( "month", new StandardSQLFunction( "month", StandardBasicTypes.INTEGER ) );
registerFunction( "year", new StandardSQLFunction( "year", StandardBasicTypes.INTEGER ) );
registerFunction( "week", new StandardSQLFunction( "week", StandardBasicTypes.INTEGER ) );
registerFunction( "quarter", new StandardSQLFunction( "quarter", StandardBasicTypes.INTEGER ) );
registerFunction( "hour", new StandardSQLFunction( "hour", StandardBasicTypes.INTEGER ) );
registerFunction( "minute", new StandardSQLFunction( "minute", StandardBasicTypes.INTEGER ) );
registerFunction( "second", new SQLFunctionTemplate( StandardBasicTypes.INTEGER, "cast(second(?1) as int)" ) );
registerFunction( "dayname", new StandardSQLFunction( "dayname", StandardBasicTypes.STRING ) );
registerFunction( "monthname", new StandardSQLFunction( "monthname", StandardBasicTypes.STRING ) );
// numeric functions
registerFunction( "abs", new StandardSQLFunction( "abs" ) );
registerFunction( "sign", new StandardSQLFunction( "sign", StandardBasicTypes.INTEGER ) );
registerFunction( "acos", new StandardSQLFunction( "acos", StandardBasicTypes.DOUBLE ) );
registerFunction( "asin", new StandardSQLFunction( "asin", StandardBasicTypes.DOUBLE ) );
registerFunction( "atan", new StandardSQLFunction( "atan", StandardBasicTypes.DOUBLE ) );
registerFunction( "cos", new StandardSQLFunction( "cos", StandardBasicTypes.DOUBLE ) );
registerFunction( "cot", new StandardSQLFunction( "cot", StandardBasicTypes.DOUBLE ) );
registerFunction( "exp", new StandardSQLFunction( "exp", StandardBasicTypes.DOUBLE ) );
registerFunction( "log", new StandardSQLFunction( "log", StandardBasicTypes.DOUBLE ) );
registerFunction( "log10", new StandardSQLFunction( "log10", StandardBasicTypes.DOUBLE ) );
registerFunction( "sin", new StandardSQLFunction( "sin", StandardBasicTypes.DOUBLE ) );
registerFunction( "sqrt", new StandardSQLFunction( "sqrt", StandardBasicTypes.DOUBLE ) );
registerFunction( "tan", new StandardSQLFunction( "tan", StandardBasicTypes.DOUBLE ) );
registerFunction( "pi", new NoArgSQLFunction( "pi", StandardBasicTypes.DOUBLE ) );
registerFunction( "rand", new StandardSQLFunction( "rand", StandardBasicTypes.FLOAT ) );
registerFunction( "radians", new StandardSQLFunction( "radians", StandardBasicTypes.DOUBLE ) );
registerFunction( "degrees", new StandardSQLFunction( "degrees", StandardBasicTypes.DOUBLE ) );
registerFunction( "round", new StandardSQLFunction( "round" ) );
registerFunction( "roundmagic", new StandardSQLFunction( "roundmagic" ) );
registerFunction( "truncate", new StandardSQLFunction( "truncate" ) );
registerFunction( "ceiling", new StandardSQLFunction( "ceiling" ) );
registerFunction( "floor", new StandardSQLFunction( "floor" ) );
// special functions
// from v. 2.2.0 ROWNUM() is supported in all modes as the equivalent of Oracle ROWNUM
if ( hsqldbVersion > 21 ) {
registerFunction("rownum",
new NoArgSQLFunction("rownum", StandardBasicTypes.INTEGER));
}
// function templates
registerFunction( "concat", new VarArgsSQLFunction( StandardBasicTypes.STRING, "(", "||", ")" ) );
getDefaultProperties().setProperty( Environment.STATEMENT_BATCH_SIZE, DEFAULT_BATCH_SIZE );
}
public String getAddColumnString() {
return "add column";
}
public boolean supportsIdentityColumns() {
return true;
}
public String getIdentityColumnString() {
return "generated by default as identity (start with 1)"; //not null is implicit
}
public String getIdentitySelectString() {
return "call identity()";
}
public String getIdentityInsertString() {
return hsqldbVersion < 20 ? "null" : "default";
}
public boolean supportsLockTimeouts() {
return false;
}
public String getForUpdateString() {
return "";
}
public boolean supportsLimit() {
return true;
}
public String getLimitString(String sql, boolean hasOffset) {
if ( hsqldbVersion < 20 ) {
return new StringBuilder( sql.length() + 10 )
.append( sql )
.insert(
sql.toLowerCase().indexOf( "select" ) + 6,
hasOffset ? " limit ? ?" : " top ?"
)
.toString();
}
else {
return new StringBuilder( sql.length() + 20 )
.append( sql )
.append( hasOffset ? " offset ? limit ?" : " limit ?" )
.toString();
}
}
public boolean bindLimitParametersFirst() {
return hsqldbVersion < 20;
}
public boolean supportsIfExistsAfterTableName() {
return true;
}
public boolean supportsColumnCheck() {
return hsqldbVersion >= 20;
}
public boolean supportsSequences() {
return true;
}
public boolean supportsPooledSequences() {
return true;
}
protected String getCreateSequenceString(String sequenceName) {
return "create sequence " + sequenceName;
}
protected String getDropSequenceString(String sequenceName) {
return "drop sequence " + sequenceName;
}
public String getSelectSequenceNextValString(String sequenceName) {
return "next value for " + sequenceName;
}
public String getSequenceNextValString(String sequenceName) {
return "call next value for " + sequenceName;
}
public String getQuerySequencesString() {
// this assumes schema support, which is present in 1.8.0 and later...
return "select sequence_name from information_schema.system_sequences";
}
public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter() {
return hsqldbVersion < 20 ? EXTRACTER_18 : EXTRACTER_20;
}
private static ViolatedConstraintNameExtracter EXTRACTER_18 = new TemplatedViolatedConstraintNameExtracter() {
/**
* Extract the name of the violated constraint from the given SQLException.
*
* @param sqle The exception that was the result of the constraint violation.
* @return The extracted constraint name.
*/
public String extractConstraintName(SQLException sqle) {
String constraintName = null;
int errorCode = JdbcExceptionHelper.extractErrorCode( sqle );
if ( errorCode == -8 ) {
constraintName = extractUsingTemplate(
"Integrity constraint violation ", " table:", sqle.getMessage()
);
}
else if ( errorCode == -9 ) {
constraintName = extractUsingTemplate(
"Violation of unique index: ", " in statement [", sqle.getMessage()
);
}
else if ( errorCode == -104 ) {
constraintName = extractUsingTemplate(
"Unique constraint violation: ", " in statement [", sqle.getMessage()
);
}
else if ( errorCode == -177 ) {
constraintName = extractUsingTemplate(
"Integrity constraint violation - no parent ", " table:",
sqle.getMessage()
);
}
return constraintName;
}
};
/**
* HSQLDB 2.0 messages have changed
* messages may be localized - therefore use the common, non-locale element " table: "
*/
private static ViolatedConstraintNameExtracter EXTRACTER_20 = new TemplatedViolatedConstraintNameExtracter() {
public String extractConstraintName(SQLException sqle) {
String constraintName = null;
int errorCode = JdbcExceptionHelper.extractErrorCode( sqle );
if ( errorCode == -8 ) {
constraintName = extractUsingTemplate(
"; ", " table: ", sqle.getMessage()
);
}
else if ( errorCode == -9 ) {
constraintName = extractUsingTemplate(
"; ", " table: ", sqle.getMessage()
);
}
else if ( errorCode == -104 ) {
constraintName = extractUsingTemplate(
"; ", " table: ", sqle.getMessage()
);
}
else if ( errorCode == -177 ) {
constraintName = extractUsingTemplate(
"; ", " table: ", sqle.getMessage()
);
}
return constraintName;
}
};
public String getSelectClauseNullString(int sqlType) {
String literal;
switch ( sqlType ) {
case Types.LONGVARCHAR:
case Types.VARCHAR:
case Types.CHAR:
literal = "cast(null as varchar(100))";
break;
case Types.LONGVARBINARY:
case Types.VARBINARY:
case Types.BINARY:
literal = "cast(null as varbinary(100))";
break;
case Types.CLOB:
literal = "cast(null as clob)";
break;
case Types.BLOB:
literal = "cast(null as blob)";
break;
case Types.DATE:
literal = "cast(null as date)";
break;
case Types.TIMESTAMP:
literal = "cast(null as timestamp)";
break;
case Types.BOOLEAN:
literal = "cast(null as boolean)";
break;
case Types.BIT:
literal = "cast(null as bit)";
break;
case Types.TIME:
literal = "cast(null as time)";
break;
default:
literal = "cast(null as int)";
}
return literal;
}
public boolean supportsUnionAll() {
return true;
}
// temporary table support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Hibernate uses this information for temporary tables that it uses for its own operations
// therefore the appropriate strategy is taken with different versions of HSQLDB
// All versions of HSQLDB support GLOBAL TEMPORARY tables where the table
// definition is shared by all users but data is private to the session
// HSQLDB 2.0 also supports session-based LOCAL TEMPORARY tables where
// the definition and data is private to the session and table declaration
// can happen in the middle of a transaction
/**
* Does this dialect support temporary tables?
*
* @return True if temp tables are supported; false otherwise.
*/
public boolean supportsTemporaryTables() {
return true;
}
/**
* With HSQLDB 2.0, the table name is qualified with MODULE to assist the drop
* statement (in-case there is a global name beginning with HT_)
*
* @param baseTableName The table name from which to base the temp table name.
*
* @return The generated temp table name.
*/
public String generateTemporaryTableName(String baseTableName) {
if ( hsqldbVersion < 20 ) {
return "HT_" + baseTableName;
}
else {
return "MODULE.HT_" + baseTableName;
}
}
/**
* Command used to create a temporary table.
*
* @return The command used to create a temporary table.
*/
public String getCreateTemporaryTableString() {
if ( hsqldbVersion < 20 ) {
return "create global temporary table";
}
else {
return "declare local temporary table";
}
}
/**
* No fragment is needed if data is not needed beyond commit, otherwise
* should add "on commit preserve rows"
*
* @return Any required postfix.
*/
public String getCreateTemporaryTablePostfix() {
return "";
}
/**
* Command used to drop a temporary table.
*
* @return The command used to drop a temporary table.
*/
public String getDropTemporaryTableString() {
return "drop table";
}
/**
* Different behavior for GLOBAL TEMPORARY (1.8) and LOCAL TEMPORARY (2.0)
*
* Possible return values and their meanings:
* - {@link Boolean#TRUE} - Unequivocally, perform the temporary table DDL
* in isolation.
* - {@link Boolean#FALSE} - Unequivocally, do not perform the
* temporary table DDL in isolation.
* - null - defer to the JDBC driver response in regards to
* {@link java.sql.DatabaseMetaData#dataDefinitionCausesTransactionCommit()}
*
*
* @return see the result matrix above.
*/
public Boolean performTemporaryTableDDLInIsolation() {
if ( hsqldbVersion < 20 ) {
return Boolean.TRUE;
}
else {
return Boolean.FALSE;
}
}
/**
* Do we need to drop the temporary table after use?
*
* todo - clarify usage by Hibernate
*
* Version 1.8 GLOBAL TEMPORARY table definitions persist beyond the end
* of the session (by default, data is cleared at commit).
*
* Version 2.x LOCAL TEMPORARY table definitions do not persist beyond
* the end of the session (by default, data is cleared at commit).
*
* @return True if the table should be dropped.
*/
public boolean dropTemporaryTableAfterUse() {
return true;
}
// current timestamp support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/**
* HSQLDB 1.8.x requires CALL CURRENT_TIMESTAMP but this should not
* be treated as a callable statement. It is equivalent to
* "select current_timestamp from dual" in some databases.
* HSQLDB 2.0 also supports VALUES CURRENT_TIMESTAMP
*
* @return True if the current timestamp can be retrieved; false otherwise.
*/
public boolean supportsCurrentTimestampSelection() {
return true;
}
/**
* Should the value returned by {@link #getCurrentTimestampSelectString}
* be treated as callable. Typically this indicates that JDBC escape
* syntax is being used...
*
* CALL CURRENT_TIMESTAMP is used but this should not
* be treated as a callable statement.
*
* @return True if the {@link #getCurrentTimestampSelectString} return
* is callable; false otherwise.
*/
public boolean isCurrentTimestampSelectStringCallable() {
return false;
}
/**
* Retrieve the command used to retrieve the current timestamp from the
* database.
*
* @return The command.
*/
public String getCurrentTimestampSelectString() {
return "call current_timestamp";
}
/**
* The name of the database-specific SQL function for retrieving the
* current timestamp.
*
* @return The function name.
*/
public String getCurrentTimestampSQLFunctionName() {
// the standard SQL function name is current_timestamp...
return "current_timestamp";
}
/**
* For HSQLDB 2.0, this is a copy of the base class implementation.
* For HSQLDB 1.8, only READ_UNCOMMITTED is supported.
*
* @param lockable The persister for the entity to be locked.
* @param lockMode The type of lock to be acquired.
*
* @return The appropriate locking strategy.
*
* @since 3.2
*/
public LockingStrategy getLockingStrategy(Lockable lockable, LockMode lockMode) {
if ( lockMode == LockMode.PESSIMISTIC_FORCE_INCREMENT ) {
return new PessimisticForceIncrementLockingStrategy( lockable, lockMode );
}
else if ( lockMode == LockMode.PESSIMISTIC_WRITE ) {
return new PessimisticWriteSelectLockingStrategy( lockable, lockMode );
}
else if ( lockMode == LockMode.PESSIMISTIC_READ ) {
return new PessimisticReadSelectLockingStrategy( lockable, lockMode );
}
else if ( lockMode == LockMode.OPTIMISTIC ) {
return new OptimisticLockingStrategy( lockable, lockMode );
}
else if ( lockMode == LockMode.OPTIMISTIC_FORCE_INCREMENT ) {
return new OptimisticForceIncrementLockingStrategy( lockable, lockMode );
}
if ( hsqldbVersion < 20 ) {
return new ReadUncommittedLockingStrategy( lockable, lockMode );
}
else {
return new SelectLockingStrategy( lockable, lockMode );
}
}
public static class ReadUncommittedLockingStrategy extends SelectLockingStrategy {
public ReadUncommittedLockingStrategy(Lockable lockable, LockMode lockMode) {
super( lockable, lockMode );
}
public void lock(Serializable id, Object version, Object object, int timeout, SessionImplementor session)
throws StaleObjectStateException, JDBCException {
if ( getLockMode().greaterThan( LockMode.READ ) ) {
LOG.hsqldbSupportsOnlyReadCommittedIsolation();
}
super.lock( id, version, object, timeout, session );
}
}
public boolean supportsCommentOn() {
return hsqldbVersion >= 20;
}
// Overridden informational metadata ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@Override
public boolean supportsEmptyInList() {
return false;
}
/**
* todo - needs usage clarification
*
* If the SELECT statement is always part of a UNION, then the type of
* parameter is resolved by v. 2.0, but not v. 1.8 (assuming the other
* SELECT in the UNION has a column reference in the same position and
* can be type-resolved).
*
* On the other hand if the SELECT statement is isolated, all versions of
* HSQLDB require casting for "select ? from .." to work.
*
* @return True if select clause parameter must be cast()ed
*
* @since 3.2
*/
public boolean requiresCastingOfParametersInSelectClause() {
return true;
}
/**
* For the underlying database, is READ_COMMITTED isolation implemented by
* forcing readers to wait for write locks to be released?
*
* @return True if writers block readers to achieve READ_COMMITTED; false otherwise.
*/
public boolean doesReadCommittedCauseWritersToBlockReaders() {
return hsqldbVersion >= 20;
}
/**
* For the underlying database, is REPEATABLE_READ isolation implemented by
* forcing writers to wait for read locks to be released?
*
* @return True if readers block writers to achieve REPEATABLE_READ; false otherwise.
*/
public boolean doesRepeatableReadCauseReadersToBlockWriters() {
return hsqldbVersion >= 20;
}
public boolean supportsLobValueChangePropogation() {
return false;
}
public String toBooleanValueString(boolean bool) {
return String.valueOf( bool );
}
public boolean supportsTupleDistinctCounts() {
return false;
}
}