Data Types

DB Access Module for Oracle OCI User's Guide
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2.3 Data Types

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

When fetching data or retrieving information about tables, the DB Access Module for Oracle OCI converts the Oracle-specific data type information provided by the database into RWDBValue::ValueTypes. This mapping is shown in Table 1, which also gives the C++ data type corresponding to the RWDBValue::ValueType.
When creating tables, the DB Access Module for Oracle OCI maps the given RWDBValue::ValueType into an Oracle-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. See also RWDBValue in the DB Interface Module Reference Guide.

Table 1: Type mapping when retrieving data

Oracle Data Type	RWDBValue:: ValueType	C++ Data Type
`CHAR(n) VARCHAR2(n)`	`String`	*RWCString*
`NCHAR(n)` `NVARCHAR2(n)`	`UString`	*RWBasicUString* orRWUString
`LONG`	`String`	*RWCString*
`CLOB`	`String`	*RWCString*
`RAW(n), LONG RAW`	`Blob`	*RWDBBlob*
`BLOB`	`Blob`	*RWDBBlob*
`NUMBER(p,0)¹ 0<p<10`	`Long`	`long int`
`NUMBER(p,0)¹` `10<=p<19`	`LongLong`	`long long`
`NUMBER(p,0) p>=19`	`Decimal`	*RWDecimalPortable*
`NUMBER(p,s) p>=10`	`Decimal`	*RWDecimalPortable*
`NUMBER(p,s)¹` `0<p<10`	`Double`	`double`
`NUMBER`	`Decimal`	*RWDecimalPortable*
`FLOAT(p)`	`Double`	`double`
`BINARY_FLOAT`	`Float`	`float`
`BINARY_DOUBLE`	`Double`	`double`
`DATE`	`DateTime`	*RWDBDateTime² RWDateTime*
`ROWID`	`String`	*RWCString*
`MLSLABEL`	`String`	*RWCString*
`TIMESTAMP`^³	`DateTime`	*RWDBDateTime²RWDateTime*

For Stored Procedures, due to lack of precision and scale information, the NUMBER column is mapped to RWDecimalPortable
RWDBDateTime is deprecated. Please use RWDateTime.
The datatypes TIMESTAMP WITH TIME ZONE and TIMESTAMP WITH LOCAL TIME ZONE are not supported.

Table 2: Type mapping when creating tables

RWDBValue::ValueType	Oracle Data Type
`Blob`	`BLOB`, if `nativeType` of the *RWDBColumn* is SQLT_BLOB `RAW(n)`, using the `storageLength` of the *RWDBColumn*, if 0 < `storageLength` <= 2000 `LONG RAW`, otherwise
`Char`, `UnsignedChar`	`NUMBER(d)`, where `d` is the number of digits needed to store the maximum value a `char` can express on the client machine
`Date`	`DATE`
`DateTime`	`DATE¹` or `TIMESTAMP(p)`, using `precision` of *RWDBColumn*, if specified
`Decimal`	`NUMBER(p,s)` using `precision` and `scale` of *RWDBColumn*
`Double`	`FLOAT(126)`
`Duration`	Not supported by DB Access Module for Oracle OCI.
`Float`	`FLOAT(p)` using `precision` of *RWDBColumn*, if specified. `FLOAT` otherwise
`Int`, `UnsignedInt`	`NUMBER(d)`, where `d` is the number of digits needed to store the maximum value an `int` can express on the client machine
`Long`, `UnsignedLong`	`NUMBER(d)`, where `d` is the number of digits needed to store the maximum value a `long` can express on the client machine
`LongLong, UnsignedLongLong`	`NUMBER(d)`, where `d` is the number of digits needed to store the maximum value a `long long` can express on the client machine
`MBString`, `UString`, `WString`	`NVARCHAR2(n)` using the `storageLength` of the *RWDBColumn*, if specified `NVARCHAR2(2000)` otherwise
`Short, UnsignedShort, Tiny, UnsignedTiny`	`NUMBER(d)`, where `d` is the number of digits needed to store the maximum value a short can express on the client machine
`String`	`CLOB`, if `nativeType` of the *RWDBColumn* is `SQLT_CLOB` `VARCHAR2(n)`, using the `storageLength` of the *RWDBColumn*, if 0 < storageLength <= 4000 `LONG`, otherwise
`NoType`	If `nativeType` of the *RWDBColumn* is: "`SQLT_NUM`, then `NUMBER(p,s)`, using `precision` and `scale` of the *RWDBColumn* "`SQLT_RDD`, then `ROWID` "`SQLT_BFLOAT` or `SQLT_IBFLOAT`, then `BINARY_FLOAT` "`SQLT_BDOUBLE` or `SQLT_IBDOUBLE`, then `BINARY_DOUBLE`

Please see Section 2.17.2 for details on switching between these types

2.3.1 Restrictions on the Use of Data Types

Oracle OCI servers place restrictions on the use of certain data types. Where possible, the DB Interface Module is flexible about data types. However, there are situations where conversions are not possible, and in these cases your application must be aware of the contexts in which certain data types can be used. Table 3 outlines the restrictions associated with each DB Interface Module type.

Table 3: Restrictions on the use of DB Interface Module data types

RWDBValue::ValueType	Restrictions
`Blob`	No restrictions
`Char`, `UnsignedChar`	No restrictions
`Date`	No restrictions
`DateTime`	Oracle's `TIMESTAMP` datatype can hold fractional seconds with a precision of 0 through 9, but *RWDBDateTime¹ and RWDateTime* are limited to milliseconds.
`Decimal`	No restrictions
`Double`	No restrictions
`Duration`	Not supported by DB Access Module for Oracle OCI
`Float`	No restrictions
`Int`, `UnsignedInt`	No restrictions
`Long`, `UnsignedLong`	No restrictions
`LongLong, UnsignedLongLong`	No restrictions
`MBString`, `UString`, `WString`	Limited to 4,000 bytes
`LongDouble`	No restrictions
`Short`, `UnsignedShort`	No restrictions
`String`	No restrictions

RWDBDateTime is deprecated. Please use RWDateTime.

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