/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.dialect;

import java.sql.CallableStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.JDBCException;
import org.hibernate.NullPrecedence;
import org.hibernate.PessimisticLockException;
import org.hibernate.boot.TempTableDdlTransactionHandling;
import org.hibernate.cfg.Environment;
import org.hibernate.dialect.function.NoArgSQLFunction;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.dialect.identity.IdentityColumnSupport;
import org.hibernate.dialect.identity.MySQLIdentityColumnSupport;
import org.hibernate.dialect.pagination.AbstractLimitHandler;
import org.hibernate.dialect.pagination.LimitHandler;
import org.hibernate.dialect.pagination.LimitHelper;
import org.hibernate.dialect.unique.MySQLUniqueDelegate;
import org.hibernate.dialect.unique.UniqueDelegate;
import org.hibernate.engine.spi.RowSelection;
import org.hibernate.exception.LockAcquisitionException;
import org.hibernate.exception.LockTimeoutException;
import org.hibernate.exception.spi.SQLExceptionConversionDelegate;
import org.hibernate.hql.spi.id.IdTableSupportStandardImpl;
import org.hibernate.hql.spi.id.MultiTableBulkIdStrategy;
import org.hibernate.hql.spi.id.local.AfterUseAction;
import org.hibernate.hql.spi.id.local.LocalTemporaryTableBulkIdStrategy;
import org.hibernate.internal.util.JdbcExceptionHelper;
import org.hibernate.mapping.Column;
import org.hibernate.type.StandardBasicTypes;

An SQL dialect for MySQL (prior to 5.x).
Author:Gavin King
/** * An SQL dialect for MySQL (prior to 5.x). * * @author Gavin King */
@SuppressWarnings("deprecation") public class MySQLDialect extends Dialect { private final UniqueDelegate uniqueDelegate; private MySQLStorageEngine storageEngine; private static final LimitHandler LIMIT_HANDLER = new AbstractLimitHandler() { @Override public String processSql(String sql, RowSelection selection) { final boolean hasOffset = LimitHelper.hasFirstRow( selection ); return sql + (hasOffset ? " limit ?, ?" : " limit ?"); } @Override public boolean supportsLimit() { return true; } };
Constructs a MySQLDialect
/** * Constructs a MySQLDialect */
public MySQLDialect() { super(); String storageEngine = Environment.getProperties().getProperty( Environment.STORAGE_ENGINE ); if(storageEngine == null) { storageEngine = System.getProperty( Environment.STORAGE_ENGINE ); } if(storageEngine == null) { this.storageEngine = getDefaultMySQLStorageEngine(); } else if( "innodb".equals( storageEngine.toLowerCase() ) ) { this.storageEngine = InnoDBStorageEngine.INSTANCE; } else if( "myisam".equals( storageEngine.toLowerCase() ) ) { this.storageEngine = MyISAMStorageEngine.INSTANCE; } else { throw new UnsupportedOperationException( "The " + storageEngine + " storage engine is not supported!" ); } registerColumnType( Types.BIT, "bit" ); registerColumnType( Types.BIGINT, "bigint" ); registerColumnType( Types.SMALLINT, "smallint" ); registerColumnType( Types.TINYINT, "tinyint" ); registerColumnType( Types.INTEGER, "integer" ); registerColumnType( Types.CHAR, "char(1)" ); registerColumnType( Types.FLOAT, "float" ); registerColumnType( Types.DOUBLE, "double precision" ); registerColumnType( Types.BOOLEAN, "bit" ); // HHH-6935 registerColumnType( Types.DATE, "date" ); registerColumnType( Types.TIME, "time" ); registerColumnType( Types.TIMESTAMP, "datetime" ); registerColumnType( Types.VARBINARY, "longblob" ); registerColumnType( Types.VARBINARY, 16777215, "mediumblob" ); registerColumnType( Types.VARBINARY, 65535, "blob" ); registerColumnType( Types.VARBINARY, 255, "tinyblob" ); registerColumnType( Types.BINARY, "binary($l)" ); registerColumnType( Types.LONGVARBINARY, "longblob" ); registerColumnType( Types.LONGVARBINARY, 16777215, "mediumblob" ); registerColumnType( Types.NUMERIC, "decimal($p,$s)" ); registerColumnType( Types.BLOB, "longblob" ); // registerColumnType( Types.BLOB, 16777215, "mediumblob" ); // registerColumnType( Types.BLOB, 65535, "blob" ); registerColumnType( Types.CLOB, "longtext" ); registerColumnType( Types.NCLOB, "longtext" ); // registerColumnType( Types.CLOB, 16777215, "mediumtext" ); // registerColumnType( Types.CLOB, 65535, "text" ); registerVarcharTypes(); registerFunction( "ascii", new StandardSQLFunction( "ascii", StandardBasicTypes.INTEGER ) ); registerFunction( "bin", new StandardSQLFunction( "bin", StandardBasicTypes.STRING ) ); registerFunction( "char_length", new StandardSQLFunction( "char_length", StandardBasicTypes.LONG ) ); registerFunction( "character_length", new StandardSQLFunction( "character_length", StandardBasicTypes.LONG ) ); registerFunction( "lcase", new StandardSQLFunction( "lcase" ) ); registerFunction( "lower", new StandardSQLFunction( "lower" ) ); registerFunction( "ltrim", new StandardSQLFunction( "ltrim" ) ); registerFunction( "ord", new StandardSQLFunction( "ord", StandardBasicTypes.INTEGER ) ); registerFunction( "quote", new StandardSQLFunction( "quote" ) ); registerFunction( "reverse", new StandardSQLFunction( "reverse" ) ); registerFunction( "rtrim", new StandardSQLFunction( "rtrim" ) ); registerFunction( "soundex", new StandardSQLFunction( "soundex" ) ); registerFunction( "space", new StandardSQLFunction( "space", StandardBasicTypes.STRING ) ); registerFunction( "ucase", new StandardSQLFunction( "ucase" ) ); registerFunction( "upper", new StandardSQLFunction( "upper" ) ); registerFunction( "unhex", new StandardSQLFunction( "unhex", StandardBasicTypes.STRING ) ); 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( "crc32", new StandardSQLFunction( "crc32", StandardBasicTypes.LONG ) ); registerFunction( "exp", new StandardSQLFunction( "exp", StandardBasicTypes.DOUBLE ) ); registerFunction( "ln", new StandardSQLFunction( "ln", StandardBasicTypes.DOUBLE ) ); registerFunction( "log", new StandardSQLFunction( "log", StandardBasicTypes.DOUBLE ) ); registerFunction( "log2", new StandardSQLFunction( "log2", StandardBasicTypes.DOUBLE ) ); registerFunction( "log10", new StandardSQLFunction( "log10", StandardBasicTypes.DOUBLE ) ); registerFunction( "pi", new NoArgSQLFunction( "pi", StandardBasicTypes.DOUBLE ) ); registerFunction( "rand", new NoArgSQLFunction( "rand", StandardBasicTypes.DOUBLE ) ); registerFunction( "sin", new StandardSQLFunction( "sin", StandardBasicTypes.DOUBLE ) ); registerFunction( "sqrt", new StandardSQLFunction( "sqrt", StandardBasicTypes.DOUBLE ) ); registerFunction( "stddev", new StandardSQLFunction("std", StandardBasicTypes.DOUBLE) ); registerFunction( "tan", new StandardSQLFunction( "tan", StandardBasicTypes.DOUBLE ) ); registerFunction( "radians", new StandardSQLFunction( "radians", StandardBasicTypes.DOUBLE ) ); registerFunction( "degrees", new StandardSQLFunction( "degrees", StandardBasicTypes.DOUBLE ) ); registerFunction( "ceiling", new StandardSQLFunction( "ceiling", StandardBasicTypes.INTEGER ) ); registerFunction( "ceil", new StandardSQLFunction( "ceil", StandardBasicTypes.INTEGER ) ); registerFunction( "floor", new StandardSQLFunction( "floor", StandardBasicTypes.INTEGER ) ); registerFunction( "round", new StandardSQLFunction( "round" ) ); registerFunction( "datediff", new StandardSQLFunction( "datediff", StandardBasicTypes.INTEGER ) ); registerFunction( "timediff", new StandardSQLFunction( "timediff", StandardBasicTypes.TIME ) ); registerFunction( "date_format", new StandardSQLFunction( "date_format", StandardBasicTypes.STRING ) ); registerFunction( "curdate", new NoArgSQLFunction( "curdate", StandardBasicTypes.DATE ) ); registerFunction( "curtime", new NoArgSQLFunction( "curtime", StandardBasicTypes.TIME ) ); registerFunction( "current_date", new NoArgSQLFunction( "current_date", StandardBasicTypes.DATE, false ) ); registerFunction( "current_time", new NoArgSQLFunction( "current_time", StandardBasicTypes.TIME, false ) ); registerFunction( "current_timestamp", new NoArgSQLFunction( "current_timestamp", StandardBasicTypes.TIMESTAMP, false ) ); registerFunction( "date", new StandardSQLFunction( "date", StandardBasicTypes.DATE ) ); registerFunction( "day", new StandardSQLFunction( "day", StandardBasicTypes.INTEGER ) ); registerFunction( "dayofmonth", new StandardSQLFunction( "dayofmonth", StandardBasicTypes.INTEGER ) ); registerFunction( "dayname", new StandardSQLFunction( "dayname", StandardBasicTypes.STRING ) ); registerFunction( "dayofweek", new StandardSQLFunction( "dayofweek", StandardBasicTypes.INTEGER ) ); registerFunction( "dayofyear", new StandardSQLFunction( "dayofyear", StandardBasicTypes.INTEGER ) ); registerFunction( "from_days", new StandardSQLFunction( "from_days", StandardBasicTypes.DATE ) ); registerFunction( "from_unixtime", new StandardSQLFunction( "from_unixtime", StandardBasicTypes.TIMESTAMP ) ); registerFunction( "hour", new StandardSQLFunction( "hour", StandardBasicTypes.INTEGER ) ); registerFunction( "last_day", new StandardSQLFunction( "last_day", StandardBasicTypes.DATE ) ); registerFunction( "localtime", new NoArgSQLFunction( "localtime", StandardBasicTypes.TIMESTAMP ) ); registerFunction( "localtimestamp", new NoArgSQLFunction( "localtimestamp", StandardBasicTypes.TIMESTAMP ) ); registerFunction( "microseconds", new StandardSQLFunction( "microseconds", StandardBasicTypes.INTEGER ) ); registerFunction( "minute", new StandardSQLFunction( "minute", StandardBasicTypes.INTEGER ) ); registerFunction( "month", new StandardSQLFunction( "month", StandardBasicTypes.INTEGER ) ); registerFunction( "monthname", new StandardSQLFunction( "monthname", StandardBasicTypes.STRING ) ); registerFunction( "now", new NoArgSQLFunction( "now", StandardBasicTypes.TIMESTAMP ) ); registerFunction( "quarter", new StandardSQLFunction( "quarter", StandardBasicTypes.INTEGER ) ); registerFunction( "second", new StandardSQLFunction( "second", StandardBasicTypes.INTEGER ) ); registerFunction( "sec_to_time", new StandardSQLFunction( "sec_to_time", StandardBasicTypes.TIME ) ); registerFunction( "sysdate", new NoArgSQLFunction( "sysdate", StandardBasicTypes.TIMESTAMP ) ); registerFunction( "time", new StandardSQLFunction( "time", StandardBasicTypes.TIME ) ); registerFunction( "timestamp", new StandardSQLFunction( "timestamp", StandardBasicTypes.TIMESTAMP ) ); registerFunction( "time_to_sec", new StandardSQLFunction( "time_to_sec", StandardBasicTypes.INTEGER ) ); registerFunction( "to_days", new StandardSQLFunction( "to_days", StandardBasicTypes.LONG ) ); registerFunction( "unix_timestamp", new StandardSQLFunction( "unix_timestamp", StandardBasicTypes.LONG ) ); registerFunction( "utc_date", new NoArgSQLFunction( "utc_date", StandardBasicTypes.STRING ) ); registerFunction( "utc_time", new NoArgSQLFunction( "utc_time", StandardBasicTypes.STRING ) ); registerFunction( "utc_timestamp", new NoArgSQLFunction( "utc_timestamp", StandardBasicTypes.STRING ) ); registerFunction( "week", new StandardSQLFunction( "week", StandardBasicTypes.INTEGER ) ); registerFunction( "weekday", new StandardSQLFunction( "weekday", StandardBasicTypes.INTEGER ) ); registerFunction( "weekofyear", new StandardSQLFunction( "weekofyear", StandardBasicTypes.INTEGER ) ); registerFunction( "year", new StandardSQLFunction( "year", StandardBasicTypes.INTEGER ) ); registerFunction( "yearweek", new StandardSQLFunction( "yearweek", StandardBasicTypes.INTEGER ) ); registerFunction( "hex", new StandardSQLFunction( "hex", StandardBasicTypes.STRING ) ); registerFunction( "oct", new StandardSQLFunction( "oct", StandardBasicTypes.STRING ) ); registerFunction( "octet_length", new StandardSQLFunction( "octet_length", StandardBasicTypes.LONG ) ); registerFunction( "bit_length", new StandardSQLFunction( "bit_length", StandardBasicTypes.LONG ) ); registerFunction( "bit_count", new StandardSQLFunction( "bit_count", StandardBasicTypes.LONG ) ); registerFunction( "encrypt", new StandardSQLFunction( "encrypt", StandardBasicTypes.STRING ) ); registerFunction( "md5", new StandardSQLFunction( "md5", StandardBasicTypes.STRING ) ); registerFunction( "sha1", new StandardSQLFunction( "sha1", StandardBasicTypes.STRING ) ); registerFunction( "sha", new StandardSQLFunction( "sha", StandardBasicTypes.STRING ) ); registerFunction( "concat", new StandardSQLFunction( "concat", StandardBasicTypes.STRING ) ); getDefaultProperties().setProperty( Environment.MAX_FETCH_DEPTH, "2" ); getDefaultProperties().setProperty( Environment.STATEMENT_BATCH_SIZE, DEFAULT_BATCH_SIZE ); uniqueDelegate = new MySQLUniqueDelegate( this ); } protected void registerVarcharTypes() { registerColumnType( Types.VARCHAR, "longtext" ); // registerColumnType( Types.VARCHAR, 16777215, "mediumtext" ); // registerColumnType( Types.VARCHAR, 65535, "text" ); registerColumnType( Types.VARCHAR, 255, "varchar($l)" ); registerColumnType( Types.LONGVARCHAR, "longtext" ); } @Override public String getAddColumnString() { return "add column"; } @Override public boolean qualifyIndexName() { return false; } @Override public String getAddForeignKeyConstraintString( String constraintName, String[] foreignKey, String referencedTable, String[] primaryKey, boolean referencesPrimaryKey) { final String cols = String.join( ", ", foreignKey ); final String referencedCols = String.join( ", ", primaryKey ); return String.format( " add constraint %s foreign key (%s) references %s (%s)", constraintName, cols, referencedTable, referencedCols ); } @Override public boolean supportsLimit() { return true; } @Override public String getDropForeignKeyString() { return " drop foreign key "; } @Override public LimitHandler getLimitHandler() { return LIMIT_HANDLER; } @Override public String getLimitString(String sql, boolean hasOffset) { return sql + (hasOffset ? " limit ?, ?" : " limit ?"); } @Override public char closeQuote() { return '`'; } @Override public char openQuote() { return '`'; } @Override public boolean canCreateCatalog() { return true; } @Override public String[] getCreateCatalogCommand(String catalogName) { return new String[] { "create database " + catalogName }; } @Override public String[] getDropCatalogCommand(String catalogName) { return new String[] { "drop database " + catalogName }; } @Override public boolean canCreateSchema() { return false; } @Override public String[] getCreateSchemaCommand(String schemaName) { throw new UnsupportedOperationException( "MySQL does not support dropping creating/dropping schemas in the JDBC sense" ); } @Override public String[] getDropSchemaCommand(String schemaName) { throw new UnsupportedOperationException( "MySQL does not support dropping creating/dropping schemas in the JDBC sense" ); } @Override public boolean supportsIfExistsBeforeTableName() { return true; } @Override public String getSelectGUIDString() { return "select uuid()"; } @Override public String getTableComment(String comment) { return " comment='" + comment + "'"; } @Override public String getColumnComment(String comment) { return " comment '" + comment + "'"; } @Override public MultiTableBulkIdStrategy getDefaultMultiTableBulkIdStrategy() { return new LocalTemporaryTableBulkIdStrategy( new IdTableSupportStandardImpl() { @Override public String getCreateIdTableCommand() { return "create temporary table if not exists"; } @Override public String getDropIdTableCommand() { return "drop temporary table"; } }, AfterUseAction.DROP, TempTableDdlTransactionHandling.NONE ); } @Override public String getCastTypeName(int code) { switch ( code ) { case Types.BOOLEAN: return "char"; case Types.INTEGER: case Types.BIGINT: case Types.SMALLINT: return smallIntegerCastTarget(); case Types.FLOAT: case Types.REAL: { return floatingPointNumberCastTarget(); } case Types.NUMERIC: return fixedPointNumberCastTarget(); case Types.VARCHAR: return "char"; case Types.VARBINARY: return "binary"; default: return super.getCastTypeName( code ); } }
Determine the cast target for Types.INTEGER, Types.BIGINT and Types.SMALLINT
Returns:The proper cast target type.
/** * Determine the cast target for {@link Types#INTEGER}, {@link Types#BIGINT} and {@link Types#SMALLINT} * * @return The proper cast target type. */
protected String smallIntegerCastTarget() { return "signed"; }
Determine the cast target for Types.FLOAT and Types.REAL (DOUBLE)
Returns:The proper cast target type.
/** * Determine the cast target for {@link Types#FLOAT} and {@link Types#REAL} (DOUBLE) * * @return The proper cast target type. */
protected String floatingPointNumberCastTarget() { // MySQL does not allow casting to DOUBLE nor FLOAT, so we have to cast these as DECIMAL. // MariaDB does allow casting to DOUBLE, although not FLOAT. return fixedPointNumberCastTarget(); }
Determine the cast target for Types.NUMERIC
Returns:The proper cast target type.
/** * Determine the cast target for {@link Types#NUMERIC} * * @return The proper cast target type. */
protected String fixedPointNumberCastTarget() { // NOTE : the precision/scale are somewhat arbitrary choices, but MySQL/MariaDB // effectively require *some* values return "decimal(" + Column.DEFAULT_PRECISION + "," + Column.DEFAULT_SCALE + ")"; } @Override public boolean supportsCurrentTimestampSelection() { return true; } @Override public boolean isCurrentTimestampSelectStringCallable() { return false; } @Override public String getCurrentTimestampSelectString() { return "select now()"; } @Override public int registerResultSetOutParameter(CallableStatement statement, int col) throws SQLException { return col; } @Override public ResultSet getResultSet(CallableStatement ps) throws SQLException { boolean isResultSet = ps.execute(); while ( !isResultSet && ps.getUpdateCount() != -1 ) { isResultSet = ps.getMoreResults(); } return ps.getResultSet(); } @Override public UniqueDelegate getUniqueDelegate() { return uniqueDelegate; } @Override public boolean supportsRowValueConstructorSyntax() { return true; } @Override public String renderOrderByElement(String expression, String collation, String order, NullPrecedence nulls) { final StringBuilder orderByElement = new StringBuilder(); if ( nulls != NullPrecedence.NONE ) { // Workaround for NULLS FIRST / LAST support. orderByElement.append( "case when " ).append( expression ).append( " is null then " ); if ( nulls == NullPrecedence.FIRST ) { orderByElement.append( "0 else 1" ); } else { orderByElement.append( "1 else 0" ); } orderByElement.append( " end, " ); } // Nulls precedence has already been handled so passing NONE value. orderByElement.append( super.renderOrderByElement( expression, collation, order, NullPrecedence.NONE ) ); return orderByElement.toString(); } // locking support @Override public String getForUpdateString() { return " for update"; } @Override public String getWriteLockString(int timeout) { return " for update"; } @Override public String getReadLockString(int timeout) { return " lock in share mode"; } // Overridden informational metadata ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @Override public boolean supportsEmptyInList() { return false; } @Override public boolean areStringComparisonsCaseInsensitive() { return true; } @Override public boolean supportsLobValueChangePropogation() { // note: at least my local MySQL 5.1 install shows this not working... return false; } @Override public boolean supportsSubqueryOnMutatingTable() { return false; } @Override public boolean supportsLockTimeouts() { // yes, we do handle "lock timeout" conditions in the exception conversion delegate, // but that's a hardcoded lock timeout period across the whole entire MySQL database. // MySQL does not support specifying lock timeouts as part of the SQL statement, which is really // what this meta method is asking. return false; } @Override public SQLExceptionConversionDelegate buildSQLExceptionConversionDelegate() { return new SQLExceptionConversionDelegate() { @Override public JDBCException convert(SQLException sqlException, String message, String sql) { switch ( sqlException.getErrorCode() ) { case 1205: { return new PessimisticLockException( message, sqlException, sql ); } case 1207: case 1206: { return new LockAcquisitionException( message, sqlException, sql ); } } final String sqlState = JdbcExceptionHelper.extractSqlState( sqlException ); if ( "41000".equals( sqlState ) ) { return new LockTimeoutException( message, sqlException, sql ); } if ( "40001".equals( sqlState ) ) { return new LockAcquisitionException( message, sqlException, sql ); } return null; } }; } @Override public String getNotExpression(String expression) { return "not (" + expression + ")"; } @Override public IdentityColumnSupport getIdentityColumnSupport() { return new MySQLIdentityColumnSupport(); } @Override public boolean isJdbcLogWarningsEnabledByDefault() { return false; } @Override public boolean supportsCascadeDelete() { return storageEngine.supportsCascadeDelete(); } @Override public String getTableTypeString() { return storageEngine.getTableTypeString( getEngineKeyword()); } protected String getEngineKeyword() { return "type"; } @Override public boolean hasSelfReferentialForeignKeyBug() { return storageEngine.hasSelfReferentialForeignKeyBug(); } @Override public boolean dropConstraints() { return storageEngine.dropConstraints(); } protected MySQLStorageEngine getDefaultMySQLStorageEngine() { return MyISAMStorageEngine.INSTANCE; } @Override protected String escapeLiteral(String literal) { return super.escapeLiteral( literal ).replace("\\", "\\\\"); } }