Datatypes

SourcePro : DB Access Module for Sybase 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 Sybase converts the Sybase-specific datatype information provided by the database 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 Sybase maps the given RWDBValue::ValueType into a Sybase-specific type. This mapping is shown in Table 2.

The RWDBValue::ValueTypes, accessible through the type() method, are 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 – Datatype mapping when retrieving data
Adaptive Server Datatypes	RWDBValue::ValueType	C++ Datatype
char(n) varchar(n) text	String	RWCString
nchar(n) nvarchar(n)	MBString¹	RWDBMBString 1
unichar(n), univarchar(n) unitext	UString	RWBasicUString or RWUString RWUString
binary(n) varbinary(n) image timestamp	Blob	RWDBBlob
bit tinyint smallint	Short	short int
int	Long	long int
decimal(p,0) p <= 9 numeric(p,0) p <= 9	Long	long int
decimal(p,0) 10 <= p < 19 numeric(p,0) 10 <= p < 19	LongLong	long long
decimal(p,0) p >= 19 numeric(p,0) p >= 19	Decimal	RWDecimalPortable
decimal(p,s) numeric(p,s)	Decimal	RWDecimalPortable
float(p) double precision	Double	double
real	Float	float
money smallmoney	Decimal	RWDecimalPortable
datetime smalldatetime²	DateTime	RWDateTime

¹ The Sybase Adaptive Server usertype value, when available, is used to differentiate standard and national character strings. See Internationalization and Localization on internationalization.

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

Table 2 – Datatype mapping when creating tables
RWDBValue::ValueType	Adaptive Server Datatype
Char UnsignedChar Tiny UnsignedTiny	tinyint
String	if 0 < length <= 255, varchar using the storageLength of the RWDBColumn, otherwise text
WString MBString	if 0 < length <= 255, nvarchar using the storageLength of the RWDBColumn, otherwise text
UString	univarchar, using the storageLength of the RWDBColumn
Blob	if 0 < length <= 255, varbinary using the storageLength of the RWDBColumn, otherwise image
Short UnsignedShort	smallint
Int UnsignedInt	int
Long UnsignedLong	int
Float	real
Double	float(p), using precision of column
Decimal	money or decimal(p,s) using precision and scale of column. See below.
Date DateTime	datetime
Duration	Not supported by the Sybase client