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 Guide.
ODBC Datatype | RWDBValue::ValueType | C++ Datatype |
|---|---|---|
SQL_NUMERIC SQL_DECIMAL | Decimal | |
SQL_BINARY SQL_VARBINARY SQL_LONGVARBINARY | Blob | |
SQL_BIT | UnsignedChar | unsigned char |
SQL_DOUBLE SQL_FLOAT | Double | double |
SQL_INTEGER | Long/UnsignedLong (32-bit architectures) Int/UnsignedInt (64-bit architectures) | long int / unsigned long int (32-bit architectures) int / unsigned int (64-bit architectures) |
SQL_INTERVAL | Duration | |
SQL_LONGVARCHAR SQL_VARCHAR SQL_CHAR | String | |
SQL_REAL | Float | float |
SQL_SMALLINT | Short UnsignedShort | short int unsigned short int |
SQL_TYPE_DATE | Date | |
DateTime | ||
SQL_WLONGVARCHAR SQL_WVARCHAR SQL_WCHAR | WString | |
SQL_BIGINT | LongLong UnsignedLongLong | long long unsigned long long |
1 Values of type SQL_TYPE_TIME and SQL_TYPE_TIMESTAMP 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.
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}1 |
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. |
1 The precision of the decimal type created is 20.
