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 ODBC converts the SQL datatype provided by ODBC 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 ODBC maps the given RWDBValue::ValueType into an SQL datatype. 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.

Table 221. Type mapping when retrieving data
ODBC Datatype	RWDBValue::ValueType	C++ Datatype
`SQL_NUMERIC` `SQL_DECIMAL`	`Decimal`	RWDecimalPortable
`SQL_BINARY` `SQL_VARBINARY` `SQL_LONGVARBINARY`	`Blob`	RWDBBlob
`SQL_BIT`	`UnsignedChar`	`unsigned char`
`SQL_DOUBLE` `SQL_FLOAT`	`Double`	`double`
`SQL_INTEGER`	`Int/UnsignedInt`	`int / unsigned int`
`SQL_INTERVAL`	`Duration`	RWDBDuration
`SQL_LONGVARCHAR` `SQL_VARCHAR` `SQL_CHAR`	`String`	RWCString
`SQL_REAL`	`Float`	`float`
`SQL_SMALLINT`	`Short` `UnsignedShort`	`short int` `unsigned short int`
`SQL_TYPE_DATE`	`Date`	RWDate
`SQL_TYPE_TIME` `SQL_TYPE_TIMESTAMP`1	`DateTime`	RWDateTime
`SQL_WLONGVARCHAR` `SQL_WVARCHAR` `SQL_WCHAR`	`WString`	RWWString
`SQL_BIGINT`	`LongLong` `UnsignedLongLong`	`long long` `unsigned long long`

Table 222. Type mapping when creating tables
RWDBValue::ValueType	Possible ODBC Datatypes: the type chosen is the first type supported by the underlying driver
`Blob`	If 0 < `length` <= 255, `{SQL_VARBINARY, SQL_BINARY, SQL_LONGVARBINARY, SQL_LONGVARCHAR}` using the `storageLength` of the RWDBColumn if applicable; otherwise, `{SQL_LONGVARBINARY,SQL_VARBINARY,SQL_BINARY, SQL_LONGVARCHAR}` using the `storageLength` of the RWDBColumn if applicable
`Char`, `UnsignedChar`	`{SQL_TINYINT, SQL_SMALLINT, SQL_INTEGER, SQL_DECIMAL, SQL_NUMERIC}`
`Date`	`{SQL_TYPE_DATE, SQL_TYPE_TIMESTAMP}`
`DateTime`	`{SQL_TYPE_TIMESTAMP, SQL_TYPE_DATE}`
`Decimal`	`{SQL_DECIMAL, SQL_NUMERIC, SQL_DOUBLE},` using the precision and scale of the RWDBColumn if applicable
`Double`	`{SQL_DOUBLE, SQL_FLOAT, SQL_DECIMAL, SQL_NUMERIC }`
`Duration`	`{SQL_INTERVAL_SECOND}`
`Float`	`{SQL_REAL, SQL_DOUBLE, SQL_FLOAT, SQL_DECIMAL, SQL_NUMERIC}` using the precision and scale of the RWDBColumn if applicable
`Int`, `UnsignedInt`	`{SQL_SMALLINT, SQL_INTEGER, SQL_REAL, SQL_DOUBLE, SQL_FLOAT, SQL_DECIMAL, SQL_NUMERIC}`
`Long`, `UnsignedLong`	`{SQL_INTEGER, SQL_REAL, SQL_DOUBLE, SQL_FLOAT, SQL_DECIMAL, SQL_NUMERIC}`
`LongLong, UnsignedLongLong`	`{SQL_BIGINT, SQL_DECIMAL, SQL_REAL}`2
`Short`, `UnsignedShort`	`{SQL_SMALLINT, SQL_INTEGER, SQL_REAL, SQL_DOUBLE, SQL_FLOAT, SQL_DECIMAL, SQL_NUMERIC}`
`String`	If 0 < `length` <= 255,`{SQL_VARCHAR, SQL_CHAR, SQL_LONGVARCHAR}`; otherwise, `{SQL_LONGVARCHAR, SQL_VARCHAR, SQL_CHAR}` using the storageLength of the RWDBColumn, if applicable.
`WString` `UString`	If 0 < `length` <= 254, `{SQL_WVARCHAR, SQL_WCHAR, SQL_WLONGVARCHAR}` using the `storageLength` of the RWDBColumn if applicable; otherwise, `{SQL_WLONGVARCHAR,SQL_WVARCHAR, SQL_WCHAR}` using the `storageLength` of the RWDBColumn if applicable.

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