Datatypes

• When fetching data or retrieving information about tables, the DB Access Module for PostgreSQL converts the PostgreSQL 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.

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 – Type mapping when retrieving data
PostgreSQL Datatype	RWDBValue:: ValueType	C++ Datatype
bigint	LongLong	long long
bigserial	LongLong	long long
bit bit varying(n)	String	RWCString
boolean	String	RWCString
box	String	RWCString
bytea	Blob	RWDBBlob
char(n)	String	RWCString
varchar(n)	String	RWCString
cidr	String	RWCString
circle	String	RWCString
date	Date	RWDate
double precision	Double	double
inet	String	RWCString
integer	Long	long int
interval(p)	Duration	RWDBDuration
line	String	RWCString
lseg	String	RWCString
macaddr	String	RWCString
money	String	RWCString
numeric	Decimal	RWDecimalPortable
path	String	RWCString
point	String	RWCString
polygon	String	RWCString
real	Float	float
smallint	Short	short int
serial	Long	long int
text	String	RWCString
time(p)¹	DateTime	RWDateTime
time(p) with time zone1	DateTime	RWDateTime
timestamp(p)1	DateTime	RWDateTime
timestamp(p) with time zone1	DateTime	RWDateTime

¹ Values of type time, time with time zone, timestamp, and timestamp with time zone 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 – Type mapping when creating tables
RWDBValue::ValueType	PostgreSQL Datatype
Blob	bytea
Char UnsignedChar Tiny UnsignedTiny Short UnsignedShort	smallint
Date	date
DateTime	timestamp[(p)] using precision of column if specified
Decimal	numeric(p,s) using precision and scale of column if specified
Duration	interval[(p)] using precision of column if specified
Double	double precision
Float	real
Int UnsignedInt	integer
Long UnsignedLong	integer
LongLong UnsignedLongLong	bigint
String	varchar(n) if storageLength is specified, else text

The PostgreSQL database places restrictions on the use of certain datatypes. Where possible, the DB Interface Module is flexible about datatypes. However, there are some situations where conversions are not possible. In these cases your applications must be aware of the contexts in which certain datatypes can be used. Table 3 outlines the known restrictions associated with each DB Interface Module type.

Table 3 – Restrictions on the use of DB Interface Module datatypes
RWDBValue::ValueType	Restrictions
Blob	No restrictions
Char UnsignedChar	No restrictions
Date	Only the PostgreSQL DateStyle ISO, MDY is supported.
DateTime	Accuracy provided by PostgreSQL is microseconds, but RWDateTime is limited to milliseconds. Only the PostgreSQL DateStyle ISO 8601 format in MDY mode is supported.
TimeTuple	Only the PostgreSQL DateStyle ISO 8601 format in MDY mode is supported.
TimeTupleOffset	This datatype is not supported.
Decimal	No restrictions
Double	No restrictions
Duration	No restrictions
Float	No restrictions
Int UnsignedInt	No restrictions
Long UnsignedLong	No restrictions
MBString	This datatype is not supported.
LongLong UnsignedLongLong	No restrictions
LongDouble	No restrictions
String	No restrictions
Short UnsignedShort	No restrictions
WString	This datatype is not supported.
UString	This datatype is not supported.