D.3.35 Modifications de la version 3.21.0

  • New keywords used: INTERVAL, EXPLAIN, READ, WRITE, BINARY.
  • Added ODBC function CHAR(num,...).
  • New operator IN. This uses a binary search to find a match.
  • New command LOCK TABLES nom_table [AS alias] {READ|WRITE} ...
  • Added --log-update option to mysqld, to get a log suitable for incremental updates.
  • New command EXPLAIN SELECT ... to get information about how the optimizer will do the join.
  • For easier client code, the client should no longer use FIELD_TYPE_TINY_BLOB, FIELD_TYPE_MEDIUM_BLOB, FIELD_TYPE_LONG_BLOB or FIELD_TYPE_VAR_STRING (as previously returned by mysql_list_fields). You should instead only use FIELD_TYPE_BLOB or FIELD_TYPE_STRING. If you want exact types, you should use the command SHOW FIELDS.
  • Added varbinary syntax: 0x###### which can be used as a string (default) or a number.
  • FIELD_TYPE_CHAR is renamed to FIELD_TYPE_TINY.
  • Changed all fields to C++ classes.
  • Removed FORM struct.
  • Fields with DEFAULT values no longer need to be NOT NULL.
  • New field types:
    ENUM
    A string which can take only a couple of defined values. The value is stored as a 1-3 byte number that is mapped automatically to a string. This is sorted according to string positions!
    SET
    A string which may have one or many string values separated with ','. The string is stored as a 1-, 2-, 3-, 4- or 8-byte number where each bit stands for a specific set member. This is sorted according to the unsigned value of the stored packed number.
  • Now all function calculation is done with double or long long. This will provide the full 64-bit range with bit functions and fix some conversions that previously could result in precision losses. One should avoid using unsigned long long columns with full 64-bit range (numbers bigger than 9223372036854775807) because calculations are done with signed long long.
  • ORDER BY will now put NULL field values first. GROUP BY will also work with NULL values.
  • Full WHERE with expressions.
  • New range optimizer that can resolve ranges when some keypart prefix is constant. Example: 
    mysql> SELECT * FROM nom_table
           WHERE key_part_1="customer"
           AND key_part_2>=10 AND key_part_2<=10;