Datatypes

SourcePro : DB Access Module for MySQL User’s Guide : Technical Information : Datatypes

Datatypes

The classes RWDBColumn and RWDBValue have an associated RWDBValue::ValueType that specifies the datatype of the database column or field being referenced. Mapping between this datatype and the database vendor type runs in both directions:

When fetching data or retrieving information about tables, the DB Access Module for MySQL converts the MySQL type value into RWDBValue::ValueTypes. This mapping is shown in Table 1, which also gives the C++ datatype corresponding to the RWDBValue::ValueType.

When creating tables, the DB Access Module for MySQL maps the given RWDBValue::ValueType into a MySQL datatype. This mapping is shown in Table 2.

The RWDBValue::ValueType, accessible through the type() method, is uniform across all Access Modules. For a complete explanation of the DB Interface Module data model, see Chapter 7, "The Data Model," in the DB Interface Module User’s Guide, and RWDBValue in the SourcePro API Reference Guide..

Table 1 – Type mapping when retrieving data
MySQL Datatype	RWDBValue::ValueType	C++ Datatype
decimal, numeric	Decimal	RWDecimalPortable
bigint	UnsignedLongLong, LongLong	unsigned long long, long long
tinyblob, blob, mediumblob, longblob	Blob	RWDBBlob
double	Double	double
float	Float	float
tinyint	Char, UnsignedChar	char, unsigned char
smallint	Short, UnsignedShort	short, unsigned short
integer, mediumint	Long, UnsignedLong	long, unsigned long
char, varchar, tinytext, mediumtext, text, longtext, enum, set	String	RWCString
date1	Date	RWDate
datetime1 time¹ timestamp²	DateTime	RWDateTime
year	UnsignedShort	unsigned short

¹ Any illegal RWDateTime value that is inserted into a TIME column is converted to “00:00:00” by the database. (MySQL converts all illegal TIME values to “00:00:00”.) Refer to your MySQL server settings to determine if the server will report this conversion as an error.

² Values of type datetime, time, and timestamp are affected by the time zone setting on either RWDBDatabase or RWDBConnection when sending and retrieving data. The time zone setting can be set programmatically with the timeZone() method in each of these classes.

Table 2 – Type mapping when creating tables
RWDBValue::ValueType	MySQL Datatypes
Blob	MEDIUMBLOB if length is RWDB_NO_TRAIT. If 0<= length <= 255 TINYBLOB. If 256 <= length <=65,535 BLOB. If 65,536 <= length <= 16,777,215 MEDIUMBLOB. Otherwise, LONGBLOB.
Tiny, UnsignedTiny, Char, UnsignedChar	TINYINT
Date	DATE
DateTime	DATETIME
Decimal (p,s)	DECIMAL using precision and scale of column. If p <= 0 defaults to 8. If s <= 0 defaults to 0.
Double	DOUBLE
Float (P)	FLOAT if precision is RWDB_NO_TRAIT. Otherwise, FLOAT (p) using precision of column.
Int, UnsignedInt, Long, UnsignedLong	INT
Short, UnsignedShort	SMALLINT
LongLong, UnsignedLongLong	BIGINT
String	MEDIUMTEXT if length is RWDB_NO_TRAIT. If 0<= length <= 255 VARCHAR(length) using the storageLength of the RWDBColumn. If 256 <= length <= 65,535 TEXT. If 65,536 <= length <= 16,777,215 MEDIUMTEXT. Otherwise LONGTEXT.