Package org.hibernate.dialect

Class PostgresPlusDialect

    • Constructor Detail

      • PostgresPlusDialect

        public PostgresPlusDialect()
        Constructs a PostgresPlusDialect

      • PostgresPlusDialect

        public PostgresPlusDialect​(DatabaseVersion version)

    • Method Detail

      • initializeFunctionRegistry

        public void initializeFunctionRegistry​(FunctionContributions functionContributions)
        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
        • var_samp(arg) - aggregate function
        • var_pop(arg) - aggregate function
        • stddev_samp(arg) - aggregate function
        • stddev_pop(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])
        • repeat(string, times)
        • pi
        • log10(arg)
        • log(base, arg)
        • sign(arg)
        • sin(arg)
        • cos(arg)
        • tan(arg)
        • asin(arg)
        • acos(arg)
        • atan(arg)
        • atan2(arg0, arg1)
        • round(arg0[, arg1])
        • truncate(arg0[, arg1])
        • sinh(arg)
        • tanh(arg)
        • cosh(arg)
        • least(arg0, arg1, ...)
        • greatest(arg0, arg1, ...)
        • degrees(arg)
        • radians(arg)
        • bitand(arg1, arg1)
        • bitor(arg1, arg1)
        • bitxor(arg1, 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 PostgreSQLDialect

      • castPattern

        public String castPattern​(CastType from,
                          CastType to)
        Description copied from class: Dialect
        Obtain a pattern for the SQL equivalent to a cast() function call. The resulting pattern must contain ?1 and ?2 placeholders for the arguments.
        Overrides:
        castPattern in class PostgreSQLDialect
        Parameters:
        from - a CastType indicating the type of the value argument
        to - a CastType indicating the type the value argument is cast to

      • currentTimestamp

        public String currentTimestamp()
        Description copied from class: Dialect
        Translation of the HQL/JPQL current_timestamp function, which maps to the Java type 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 PostgreSQLDialect

      • timestampdiffPattern

        public String timestampdiffPattern​(TemporalUnit unit,
                                   TemporalType fromTemporalType,
                                   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 PostgreSQLDialect
        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

      • isEmptyStringTreatedAsNull

        public boolean isEmptyStringTreatedAsNull()
        Description copied from class: Dialect
        Return whether the dialect considers an empty string value to be null.
        Overrides:
        isEmptyStringTreatedAsNull in class Dialect
        Returns:
        boolean True if an empty string is treated as null, false otherwise.

      • registerResultSetOutParameter

        public int registerResultSetOutParameter​(CallableStatement statement,
                                         int col)
                                  throws SQLException
        Description copied from class: Dialect
        Registers a parameter capable of returning a ResultSet by position, either an OUT parameter, or a REF_CURSOR parameter as defined in Java 8.
        Overrides:
        registerResultSetOutParameter in class PostgreSQLDialect
        Parameters:
        statement - The callable statement.
        col - 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.

      • getSelectGUIDString

        public String getSelectGUIDString()
        Description copied from class: Dialect
        Get the command used to select a GUID from the database.

        Optional operation.

        Overrides:
        getSelectGUIDString in class Dialect
        Returns:
        The appropriate command.