Class H2Dialect

    • Method Detail

      • columnType

        protected String columnType​(int sqlTypeCode)
        Description copied from class: Dialect
        The column type name for a given JDBC type code defined in Types or SqlTypes. This default implementation returns the ANSI-standard type name.

        This method may be overridden by concrete Dialects as an alternative to Dialect.registerColumnTypes(TypeContributions, ServiceRegistry) for simple registrations.

        Overrides:
        columnType in class Dialect
        Parameters:
        sqlTypeCode - a SQL type code
        Returns:
        a column type name, with $l, $p, $s placeholders for length, precision, scale
        See Also:
        SqlTypes
      • contributeTypes

        public void contributeTypes​(TypeContributions typeContributions,
                                    ServiceRegistry serviceRegistry)
        Description copied from class: Dialect
        Allows the Dialect to contribute additional types
        Overrides:
        contributeTypes in class Dialect
        Parameters:
        typeContributions - Callback to contribute the types
        serviceRegistry - The service registry
      • hasOddDstBehavior

        public boolean hasOddDstBehavior()
      • initializeFunctionRegistry

        public void initializeFunctionRegistry​(QueryEngine queryEngine)
        Description copied from class: Dialect
        Initialize the given registry with any dialect-specific functions.

        Support for certain SQL functions is required, and if the database does not support a required function, then the dialect must define a way to emulate it.

        These required functions include the functions defined by the JPA query language specification:

        • avg(arg) - aggregate function
        • count([distinct ]arg) - aggregate function
        • max(arg) - aggregate function
        • min(arg) - aggregate function
        • sum(arg) - aggregate function
        • coalesce(arg0, arg1, ...)
        • nullif(arg0, arg1)
        • lower(arg)
        • upper(arg)
        • length(arg)
        • concat(arg0, arg1, ...)
        • locate(pattern, string[, start])
        • substring(string, start[, length])
        • trim([[spec ][character ]from] string)
        • abs(arg)
        • mod(arg0, arg1)
        • sqrt(arg)
        • current date
        • current time
        • current timestamp
        Along with an additional set of functions defined by ANSI SQL:
        • any(arg) - aggregate function
        • every(arg) - aggregate function
        • cast(arg as Type)
        • extract(field from arg)
        • ln(arg)
        • exp(arg)
        • power(arg0, arg1)
        • floor(arg)
        • ceiling(arg)
        • position(pattern in string)
        • substring(string from start[ for length])
        • overlay(string placing replacement from start[ for length])
        And the following functions for working with java.time types:
        • local date
        • local time
        • local datetime
        • offset datetime
        • instant
        And a number of additional "standard" functions:
        • left(string, length)
        • right(string, length)
        • replace(string, pattern, replacement)
        • pad(string with length spec[ character])
        • log10(arg)
        • sign(arg)
        • sin(arg)
        • cos(arg)
        • tan(arg)
        • asin(arg)
        • acos(arg)
        • atan(arg)
        • atan2(arg0, arg1)
        • round(arg0, arg1)
        • least(arg0, arg1, ...)
        • greatest(arg0, arg1, ...)
        • format(datetime as pattern)
        • collate(string as collation)
        • str(arg) - synonym of cast(a as String)
        • ifnull(arg0, arg1) - synonym of coalesce(a, b)
        Finally, the following functions are defined as abbreviations for extract(), and desugared by the parser:
        • second(arg) - synonym of extract(second from a)
        • minute(arg) - synonym of extract(minute from a)
        • hour(arg) - synonym of extract(hour from a)
        • day(arg) - synonym of extract(day from a)
        • month(arg) - synonym of extract(month from a)
        • year(arg) - synonym of extract(year from a)
        Note that according to this definition, the second() function returns a floating point value, contrary to the integer type returned by the native function with this name on many databases. Thus, we don't just naively map these HQL functions to the native SQL functions with the same names.
        Overrides:
        initializeFunctionRegistry in class Dialect
      • getMaxVarcharLength

        public int getMaxVarcharLength()
        Description copied from class: Dialect
        The longest possible length of a Types.VARCHAR-like column. For longer column lengths, use some sort of text-like type for the column.
        Overrides:
        getMaxVarcharLength in class Dialect
      • currentTime

        public String currentTime()
        Description copied from class: Dialect
        Translation of the HQL/JPQL current_time function, which maps to the Java type java.sql.Time which is a time with no time zone. This contradicts ANSI SQL where current_time has the type TIME WITH TIME ZONE.

        It is recommended to override this in dialects for databases which support localtime or time at local.

        Overrides:
        currentTime in class Dialect
      • currentTimestamp

        public String currentTimestamp()
        Description copied from class: Dialect
        Translation of the HQL/JPQL current_timestamp function, which maps to the Java type java.sql.Timestamp which is a datetime with no time zone. This contradicts ANSI SQL where current_timestamp has the type TIMESTAMP WITH TIME ZONE.

        It is recommended to override this in dialects for databases which support localtimestamp or timestamp at local.

        Overrides:
        currentTimestamp in class Dialect
      • currentTimestampWithTimeZone

        public String currentTimestampWithTimeZone()
        Description copied from class: Dialect
        Translation of the HQL offset_datetime function, which maps to the Java type java.time.OffsetDateTime which is a datetime with a time zone. This in principle correctly maps to the ANSI SQL current_timestamp which has the type TIMESTAMP WITH TIME ZONE.
        Overrides:
        currentTimestampWithTimeZone in class Dialect
      • extractPattern

        public String extractPattern​(TemporalUnit unit)
        In H2, the extract() function does not return fractional seconds for the field TemporalUnit.SECOND. We work around this here with two calls to extract().
        Overrides:
        extractPattern in class Dialect
        Parameters:
        unit - the first argument
      • timestampaddPattern

        public String timestampaddPattern​(TemporalUnit unit,
                                          jakarta.persistence.TemporalType temporalType,
                                          IntervalType intervalType)
        Description copied from class: Dialect
        Obtain a pattern for the SQL equivalent to a timestampadd() function call. The resulting pattern must contain ?1, ?2, and ?3 placeholders for the arguments.
        Overrides:
        timestampaddPattern in class Dialect
        Parameters:
        unit - The unit to add to the temporal
        temporalType - The type of the temporal
        intervalType - The type of interval to add or null if it's not a native interval
      • timestampdiffPattern

        public String timestampdiffPattern​(TemporalUnit unit,
                                           jakarta.persistence.TemporalType fromTemporalType,
                                           jakarta.persistence.TemporalType toTemporalType)
        Description copied from class: Dialect
        Obtain a pattern for the SQL equivalent to a timestampdiff() function call. The resulting pattern must contain ?1, ?2, and ?3 placeholders for the arguments.
        Overrides:
        timestampdiffPattern in class Dialect
        Parameters:
        unit - the first argument
        fromTemporalType - true if the first argument is a timestamp, false if a date
        toTemporalType - true if the second argument is
      • supportsTemporalLiteralOffset

        public boolean supportsTemporalLiteralOffset()
        Description copied from class: Dialect
        Whether the Dialect supports timezone offset in temporal literals.
        Overrides:
        supportsTemporalLiteralOffset in class Dialect
      • supportsIfExistsAfterTableName

        public boolean supportsIfExistsAfterTableName()
        Description copied from class: Dialect
        For dropping a table, can the phrase "if exists" be applied after the table name?

        NOTE : Only one or the other (or neither) of this and Dialect.supportsIfExistsBeforeTableName() should return true

        Overrides:
        supportsIfExistsAfterTableName in class Dialect
        Returns:
        true if the "if exists" can be applied after the table name
      • supportsIfExistsBeforeTableName

        public boolean supportsIfExistsBeforeTableName()
        Description copied from class: Dialect
        For dropping a table, can the phrase "if exists" be applied before the table name?

        NOTE : Only one or the other (or neither) of this and Dialect.supportsIfExistsAfterTableName() should return true

        Overrides:
        supportsIfExistsBeforeTableName in class Dialect
        Returns:
        true if the "if exists" can be applied before the table name
      • supportsIfExistsAfterAlterTable

        public boolean supportsIfExistsAfterAlterTable()
        Description copied from class: Dialect
        For an "alter table", can the phrase "if exists" be applied?
        Overrides:
        supportsIfExistsAfterAlterTable in class Dialect
        Returns:
        true if the "if exists" can be applied after ALTER TABLE
      • supportsIfExistsBeforeConstraintName

        public boolean supportsIfExistsBeforeConstraintName()
        Description copied from class: Dialect
        For dropping a constraint with an "alter table", can the phrase "if exists" be applied before the constraint name?

        NOTE : Only one or the other (or neither) of this and Dialect.supportsIfExistsAfterConstraintName() should return true

        Overrides:
        supportsIfExistsBeforeConstraintName in class Dialect
        Returns:
        true if the "if exists" can be applied before the constraint name
      • getCascadeConstraintsString

        public String getCascadeConstraintsString()
        Description copied from class: Dialect
        The keyword that specifies that a drop table operation should be cascaded to its constraints, typically " cascade" where the leading space is required, or the empty string if there is no such keyword in this dialect.
        Overrides:
        getCascadeConstraintsString in class Dialect
        Returns:
        The cascade drop keyword, if any, with a leading space
      • supportsCommentOn

        public boolean supportsCommentOn()
        Description copied from class: Dialect
        Does this dialect/database support commenting on tables, columns, etc?
        Overrides:
        supportsCommentOn in class Dialect
        Returns:
        true if commenting is supported
      • dropConstraints

        public boolean dropConstraints()
        Description copied from class: Dialect
        Do we need to drop constraints before dropping tables in this dialect?
        Overrides:
        dropConstraints in class Dialect
        Returns:
        True if constraints must be dropped prior to dropping the table; false otherwise.
      • getQuerySequencesString

        public String getQuerySequencesString()
        Description copied from class: Dialect
        Get the select command used retrieve the names of all sequences.
        Overrides:
        getQuerySequencesString in class Dialect
        Returns:
        The select command; or null if sequences are not supported.
      • buildSQLExceptionConversionDelegate

        public SQLExceptionConversionDelegate buildSQLExceptionConversionDelegate()
        Description copied from class: Dialect
        Build an instance of a SQLExceptionConversionDelegate for interpreting dialect-specific error or SQLState codes.

        If this method is overridden to return a non-null value, the default SQLExceptionConverter will use the returned SQLExceptionConversionDelegate in addition to the following standard delegates:

        1. a "static" delegate based on the JDBC 4 defined SQLException hierarchy;
        2. a delegate that interprets SQLState codes for either X/Open or SQL-2003 codes, depending on java.sql.DatabaseMetaData#getSQLStateType

        It is strongly recommended that specific Dialect implementations override this method, since interpretation of a SQL error is much more accurate when based on the vendor-specific ErrorCode rather than the SQLState.

        Specific Dialects may override to return whatever is most appropriate for that vendor.

        Overrides:
        buildSQLExceptionConversionDelegate in class Dialect
        Returns:
        The SQLExceptionConversionDelegate for this dialect
      • supportsCurrentTimestampSelection

        public boolean supportsCurrentTimestampSelection()
        Description copied from class: Dialect
        Does this dialect support a way to retrieve the database's current timestamp value?
        Overrides:
        supportsCurrentTimestampSelection in class Dialect
        Returns:
        True if the current timestamp can be retrieved; false otherwise.
      • getCurrentTimestampSelectString

        public String getCurrentTimestampSelectString()
        Description copied from class: Dialect
        Retrieve the command used to retrieve the current timestamp from the database.
        Overrides:
        getCurrentTimestampSelectString in class Dialect
        Returns:
        The command.
      • supportsTupleCounts

        public boolean supportsTupleCounts()
        Description copied from class: Dialect
        Does this dialect support `count(a,b)`?
        Overrides:
        supportsTupleCounts in class Dialect
        Returns:
        True if the database supports counting tuples; false otherwise.
      • doesReadCommittedCauseWritersToBlockReaders

        public boolean doesReadCommittedCauseWritersToBlockReaders()
        Description copied from class: Dialect
        For the underlying database, is READ_COMMITTED isolation implemented by forcing readers to wait for write locks to be released?
        Overrides:
        doesReadCommittedCauseWritersToBlockReaders in class Dialect
        Returns:
        True if writers block readers to achieve READ_COMMITTED; false otherwise.
      • supportsOffsetInSubquery

        public boolean supportsOffsetInSubquery()
        Description copied from class: Dialect
        Does this dialect support offset in subqueries? Ex: select * from Table1 where col1 in (select col1 from Table2 order by col2 limit 1 offset 1)
        Overrides:
        supportsOffsetInSubquery in class Dialect
        Returns:
        boolean
      • supportsWindowFunctions

        public boolean supportsWindowFunctions()
        Description copied from class: Dialect
        Does this dialect support window functions like row_number() over (..)?
        Overrides:
        supportsWindowFunctions in class Dialect
        Returns:
        true if the underlying database supports window functions, false otherwise. The default is false.
      • supportsFetchClause

        public boolean supportsFetchClause​(FetchClauseType type)
        Description copied from class: Dialect
        Does this dialect support the given fetch clause type.
        Overrides:
        supportsFetchClause in class Dialect
        Parameters:
        type - The fetch clause type
        Returns:
        true if the underlying database supports the given fetch clause type, false otherwise. The default is false.
      • registerResultSetOutParameter

        public int registerResultSetOutParameter​(CallableStatement statement,
                                                 int position)
                                          throws SQLException
        Description copied from class: Dialect
        Registers a parameter (either OUT, or the new REF_CURSOR param type available in Java 8) capable of returning ResultSet *by position*. Pre-Java 8, registering such ResultSet-returning parameters varied greatly across database and drivers; hence its inclusion as part of the Dialect contract.
        Overrides:
        registerResultSetOutParameter in class Dialect
        Parameters:
        statement - The callable statement.
        position - The bind position at which to register the output param.
        Returns:
        The number of (contiguous) bind positions used.
        Throws:
        SQLException - Indicates problems registering the param.
      • getQueryHintString

        public String getQueryHintString​(String query,
                                         String hints)
        Description copied from class: Dialect
        Apply a hint to the query. The entire query is provided, allowing the Dialect full control over the placement and syntax of the hint. By default, ignore the hint and simply return the query.
        Overrides:
        getQueryHintString in class Dialect
        Parameters:
        query - The query to which to apply the hint.
        hints - The hints to apply
        Returns:
        The modified SQL
      • appendDatetimeFormat

        public void appendDatetimeFormat​(SqlAppender appender,
                                         String format)
        Description copied from class: Dialect
        Translate the given datetime format string from the pattern language defined by Java's DateTimeFormatter to whatever pattern language is understood by the native datetime formatting function for this database (often the to_char() function).

        Since it's never possible to translate all of the pattern letter sequences understood by DateTimeFormatter, only the following subset of pattern letters is accepted by Hibernate:

        • G: era
        • y: year of era
        • Y: year of week-based year
        • M: month of year
        • w: week of week-based year (ISO week number)
        • W: week of month
        • E: day of week (name)
        • e: day of week (number)
        • d: day of month
        • D: day of year
        • a: AM/PM
        • H: hour of day (24 hour time)
        • h: hour of AM/PM (12 hour time)
        • m: minutes
        • s: seconds
        • z,Z,x: timezone offset
        In addition, punctuation characters and single-quoted literal strings are accepted.

        Appends a pattern accepted by the function that formats dates and times in this dialect to a SQL fragment that is being constructed.

        Overrides:
        appendDatetimeFormat in class Dialect