@Override
public IdentifierHelper buildIdentifierHelper(IdentifierHelperBuilder builder, DatabaseMetaData dbMetaData)
        throws SQLException {
    // PostgreSQL considers unquoted identifiers lowercase
    // https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS
    builder.setUnquotedCaseStrategy(IdentifierCaseStrategy.LOWER);
    // then delegate to the database metadata driver identifier casing selection
    // which can override these settings.
    return super.buildIdentifierHelper(builder, dbMetaData);
}
 

@Override
public IdentifierHelper buildIdentifierHelper(IdentifierHelperBuilder builder, DatabaseMetaData dbMetaData)
        throws SQLException {
    // H2 by default consider identifiers as upper case
    // unless DATABASE_TO_UPPER=false but that's not the default
    // and Thomas Mueller says it's normal ANSI-SQL SQL-92 behavior
    // http://h2-database.66688.n3.nabble.com/Case-of-column-name-td3485519.html
    // http://www.h2database.com/html/grammar.html#name
    // DATABASE_TO_LOWER=TRUE will come with H2's next version as of Feb 2019 but only for PostgreSQL compat
    builder.setUnquotedCaseStrategy(IdentifierCaseStrategy.UPPER);
    // then delegate to the database metadata driver identifier casing selection
    // which can override these settings.
    return super.buildIdentifierHelper(builder, dbMetaData);
}
 

@Override
public IdentifierHelper buildIdentifierHelper(IdentifierHelperBuilder builder, DatabaseMetaData dbMetaData)
        throws SQLException {
    // PostgreSQL considers unquoted identifiers lowercase
    // https://www.postgresql.org/docs/current/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS
    builder.setUnquotedCaseStrategy(IdentifierCaseStrategy.LOWER);
    // then delegate to the database metadata driver identifier casing selection
    // which can override these settings.
    return super.buildIdentifierHelper(builder, dbMetaData);
}
 

/**
 * Constructor form used when the JDBC {@link java.sql.DatabaseMetaData} is not available.
 *
 * @param serviceRegistry The service registry
 * @param dialect The resolved dialect.
 */
public JdbcEnvironmentImpl(ServiceRegistryImplementor serviceRegistry, Dialect dialect) {
	this.dialect = dialect;

	final ConfigurationService cfgService = serviceRegistry.getService( ConfigurationService.class );

	NameQualifierSupport nameQualifierSupport = dialect.getNameQualifierSupport();
	if ( nameQualifierSupport == null ) {
		// assume both catalogs and schemas are supported
		nameQualifierSupport = NameQualifierSupport.BOTH;
	}
	this.nameQualifierSupport = nameQualifierSupport;

	this.sqlExceptionHelper = buildSqlExceptionHelper( dialect, logWarnings( cfgService, dialect ) );

	final IdentifierHelperBuilder identifierHelperBuilder = IdentifierHelperBuilder.from( this );
	identifierHelperBuilder.setGloballyQuoteIdentifiers( globalQuoting( cfgService ) );
	identifierHelperBuilder.setSkipGlobalQuotingForColumnDefinitions( globalQuotingSkippedForColumnDefinitions( cfgService ) );
	identifierHelperBuilder.setAutoQuoteKeywords( autoKeywordQuoting( cfgService ) );
	identifierHelperBuilder.setNameQualifierSupport( nameQualifierSupport );

	IdentifierHelper identifierHelper = null;
	ExtractedDatabaseMetaDataImpl.Builder dbMetaDataBuilder = new ExtractedDatabaseMetaDataImpl.Builder( this );
	try {
		identifierHelper = dialect.buildIdentifierHelper( identifierHelperBuilder, null );
		dbMetaDataBuilder.setSupportsNamedParameters( dialect.supportsNamedParameters( null ) );
	}
	catch (SQLException sqle) {
		// should never ever happen
		log.debug( "There was a problem accessing DatabaseMetaData in building the JdbcEnvironment", sqle );
	}
	if ( identifierHelper == null ) {
		identifierHelper = identifierHelperBuilder.build();
	}
	this.identifierHelper = identifierHelper;

	this.extractedMetaDataSupport = dbMetaDataBuilder.build();

	this.currentCatalog = identifierHelper.toIdentifier(
			cfgService.getSetting( AvailableSettings.DEFAULT_CATALOG, StandardConverters.STRING )
	);
	this.currentSchema = Identifier.toIdentifier(
			cfgService.getSetting( AvailableSettings.DEFAULT_SCHEMA, StandardConverters.STRING )
	);

	this.qualifiedObjectNameFormatter = new QualifiedObjectNameFormatterStandardImpl( nameQualifierSupport );

	this.lobCreatorBuilder = LobCreatorBuilderImpl.makeLobCreatorBuilder();
}
 

/**
 * Constructor form used from testing
 *
 * @param dialect The dialect
 */
public JdbcEnvironmentImpl(DatabaseMetaData databaseMetaData, Dialect dialect) throws SQLException {
	this.dialect = dialect;

	this.sqlExceptionHelper = buildSqlExceptionHelper( dialect, false );

	this.extractedMetaDataSupport = new ExtractedDatabaseMetaDataImpl.Builder( this )
			.apply( databaseMetaData )
			.setSupportsNamedParameters( databaseMetaData.supportsNamedParameters() )
			.build();

	NameQualifierSupport nameQualifierSupport = dialect.getNameQualifierSupport();
	if ( nameQualifierSupport == null ) {
		nameQualifierSupport = determineNameQualifierSupport( databaseMetaData );
	}
	this.nameQualifierSupport = nameQualifierSupport;

	final IdentifierHelperBuilder identifierHelperBuilder = IdentifierHelperBuilder.from( this );
	identifierHelperBuilder.setNameQualifierSupport( nameQualifierSupport );
	IdentifierHelper identifierHelper = null;
	try {
		identifierHelper = dialect.buildIdentifierHelper( identifierHelperBuilder, databaseMetaData );
	}
	catch (SQLException sqle) {
		// should never ever happen
		log.debug( "There was a problem accessing DatabaseMetaData in building the JdbcEnvironment", sqle );
	}
	if ( identifierHelper == null ) {
		identifierHelper = identifierHelperBuilder.build();
	}
	this.identifierHelper = identifierHelper;

	this.currentCatalog = null;
	this.currentSchema = null;

	this.qualifiedObjectNameFormatter = new QualifiedObjectNameFormatterStandardImpl(
			nameQualifierSupport,
			databaseMetaData
	);

	this.lobCreatorBuilder = LobCreatorBuilderImpl.makeLobCreatorBuilder();
}
 

/**
 * The main constructor form.  Builds a JdbcEnvironment using the available DatabaseMetaData
 *
 * @param serviceRegistry The service registry
 * @param dialect The resolved dialect
 * @param databaseMetaData The available DatabaseMetaData
 *
 * @throws SQLException
 */
public JdbcEnvironmentImpl(
		ServiceRegistryImplementor serviceRegistry,
		Dialect dialect,
		DatabaseMetaData databaseMetaData) throws SQLException {
	this.dialect = dialect;

	final ConfigurationService cfgService = serviceRegistry.getService( ConfigurationService.class );

	this.sqlExceptionHelper = buildSqlExceptionHelper( dialect, logWarnings( cfgService, dialect ) );

	this.extractedMetaDataSupport = new ExtractedDatabaseMetaDataImpl.Builder( this )
			.apply( databaseMetaData )
			.setConnectionSchemaName( determineCurrentSchemaName( databaseMetaData, serviceRegistry, dialect ) )
			.setSupportsNamedParameters(dialect.supportsNamedParameters(databaseMetaData))
			.build();

	NameQualifierSupport nameQualifierSupport = dialect.getNameQualifierSupport();
	if ( nameQualifierSupport == null ) {
		nameQualifierSupport = determineNameQualifierSupport( databaseMetaData );
	}
	this.nameQualifierSupport = nameQualifierSupport;

	final IdentifierHelperBuilder identifierHelperBuilder = IdentifierHelperBuilder.from( this );
	identifierHelperBuilder.setGloballyQuoteIdentifiers( globalQuoting( cfgService ) );
	identifierHelperBuilder.setSkipGlobalQuotingForColumnDefinitions( globalQuotingSkippedForColumnDefinitions( cfgService ) );
	identifierHelperBuilder.setAutoQuoteKeywords( autoKeywordQuoting( cfgService ) );
	identifierHelperBuilder.setNameQualifierSupport( nameQualifierSupport );
	IdentifierHelper identifierHelper = null;
	try {
		identifierHelper = dialect.buildIdentifierHelper( identifierHelperBuilder, databaseMetaData );
	}
	catch (SQLException sqle) {
		// should never ever happen
		log.debug( "There was a problem accessing DatabaseMetaData in building the JdbcEnvironment", sqle );
	}
	if ( identifierHelper == null ) {
		identifierHelper = identifierHelperBuilder.build();
	}
	this.identifierHelper = identifierHelper;

	// and that current-catalog and current-schema happen after it
	this.currentCatalog = identifierHelper.toIdentifier( extractedMetaDataSupport.getConnectionCatalogName() );
	this.currentSchema = identifierHelper.toIdentifier( extractedMetaDataSupport.getConnectionSchemaName() );

	this.qualifiedObjectNameFormatter = new QualifiedObjectNameFormatterStandardImpl(
			nameQualifierSupport,
			databaseMetaData
	);

	this.typeInfoSet.addAll( TypeInfo.extractTypeInfo( databaseMetaData ) );

	this.lobCreatorBuilder = LobCreatorBuilderImpl.makeLobCreatorBuilder(
			cfgService.getSettings(),
			databaseMetaData.getConnection()
	);
}
 

@Override
public IdentifierHelper buildIdentifierHelper(
        IdentifierHelperBuilder builder, DatabaseMetaData dbMetaData) throws SQLException {
    return getInstance().buildIdentifierHelper(builder, dbMetaData);
}
 

@Override
public IdentifierHelper buildIdentifierHelper(
		IdentifierHelperBuilder builder, DatabaseMetaData dbMetaData) throws SQLException {
	builder.applyIdentifierCasing( dbMetaData );

	builder.applyReservedWords( dbMetaData );

	builder.applyReservedWords( getKeywords() );

	builder.setNameQualifierSupport( getNameQualifierSupport() );

	return builder.build();
}
 

/**
 * Build the IdentifierHelper indicated by this Dialect for handling identifier conversions.
 * Returning {@code null} is allowed and indicates that Hibernate should fallback to building a
 * "standard" helper.  In the fallback path, any changes made to the IdentifierHelperBuilder
 * during this call will still be incorporated into the built IdentifierHelper.
 * <p/>
 * The incoming builder will have the following set:<ul>
 *     <li>{@link IdentifierHelperBuilder#isGloballyQuoteIdentifiers()}</li>
 *     <li>{@link IdentifierHelperBuilder#getUnquotedCaseStrategy()} - initialized to UPPER</li>
 *     <li>{@link IdentifierHelperBuilder#getQuotedCaseStrategy()} - initialized to MIXED</li>
 * </ul>
 * <p/>
 * By default Hibernate will do the following:<ul>
 *     <li>Call {@link IdentifierHelperBuilder#applyIdentifierCasing(DatabaseMetaData)}
 *     <li>Call {@link IdentifierHelperBuilder#applyReservedWords(DatabaseMetaData)}
 *     <li>Applies {@link AnsiSqlKeywords#sql2003()} as reserved words</li>
 *     <li>Applies the {#link #sqlKeywords} collected here as reserved words</li>
 *     <li>Applies the Dialect's NameQualifierSupport, if it defines one</li>
 * </ul>
 *
 * @param builder A semi-configured IdentifierHelper builder.
 * @param dbMetaData Access to the metadata returned from the driver if needed and if available.  WARNING: may be {@code null}
 *
 * @return The IdentifierHelper instance to use, or {@code null} to indicate Hibernate should use its fallback path
 *
 * @throws SQLException Accessing the DatabaseMetaData can throw it.  Just re-throw and Hibernate will handle.
 *
 * @see #getNameQualifierSupport()
 */
public IdentifierHelper buildIdentifierHelper(
		IdentifierHelperBuilder builder,
		DatabaseMetaData dbMetaData) throws SQLException {
	builder.applyIdentifierCasing( dbMetaData );

	builder.applyReservedWords( dbMetaData );
	builder.applyReservedWords( AnsiSqlKeywords.INSTANCE.sql2003() );
	builder.applyReservedWords( sqlKeywords );

	builder.setNameQualifierSupport( getNameQualifierSupport() );

	return builder.build();
}