Data conversion

Db2 ODBC manages the transfer and any required conversion of data between the application and the database server. However, not all data conversions are supported.

Before the data transfer actually takes place, the source, target, or both data types are indicated when calling SQLBindParameter(), SQLBindCol(), or SQLGetData(). These functions use symbolic type names shown to identify the data types involved in the data transfer.

Example: The following SQLBindParameter() call binds a parameter marker that corresponds to an SQL data type of DECIMAL(5,3) to an application's C buffer type of double: 
SQLBindParameter (hstmt, 1, SQL_PARAM_INPUT, SQL_C_DOUBLE,
                  SQL_DECIMAL, 5, 3, double_ptr, NULL);

Supported data conversions lists the data conversions that Db2 ODBC supports.

The first column contains the data type of the SQL data type. The remaining columns represent the C data types. If the C data type columns contain:
D
The conversion is supported and this is the default conversion for the SQL data type.
X
All IBM® databases support the conversion.
blank
No IBM databases supports the conversion.
Table 1. Supported data conversions
SQL
data type
S
Q
L
_
C
_
C
H
A
R
S
Q
L
_
C
_
W
C
H
A
R
S
Q
L
_
C
_
B
I
N
A
R
Y
X
M
L
S
Q
L
_
C
_
D
B
C
H
A
R
S
Q
L
_
C
_
B
I
T
S
Q
L
_
C
_
T
I
N
Y
I
N
T
S
Q
L
_
C
_
S
H
O
R
T
S
Q
L
_
C
_
L
O
N
G
S
Q
L
_
C
_
B
I
G
I
N
T
S
Q
L
_
C
_
S
B
I
G
I
N
T
S
Q
L
_
C
_
F
L
O
A
T
S
Q
L
_
C
_
D
O
U
B
L
E
S
Q
L
_
C
_
D
E
C
I
M
A
L
6
4
S
Q
L
_
C
_
D
E
C
I
M
A
L
1
2
8
S
Q
L
_
C
_
T
Y
P
E
_
D
A
T
E
S
Q
L
_
C
_
T
Y
P
E
_
T
I
M
E
S
Q
L
_
C
_
T
Y
P
E
_
T
I
M
E
S
T
A
M
P
S
Q
L
_
C
_
T
Y
P
E
_
T
I
M
E
S
T
A
M
P
_
E
X
T
S
Q
L
_
C
_
T
Y
P
E
_
T
I
M
E
S
T
A
M
P
_
E
X
T
_
T
Z
S
Q
L
_
C
_
B
I
N
A
R
Y
S
Q
L
_
C
_
C
L
O
B
_
L
O
C
A
T
O
R
S
Q
L
_
C
_
B
L
O
B
_
L
O
C
A
T
O
R
S
Q
L
_
C
_
D
B
C
L
O
B
_
L
O
C
A
T
O
R
SQL_CHAR
D1
X2
  
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
SQL_
VARCHAR
D1
X2
  
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
SQL_
LONG
VARCHAR
D1
X2
  
X
X
X
SQL_
BINARY
X1
X2
  
D
SQL_
VARBINARY
X1
X2
  
D
SQL_
LONG
VARBINARY
X1
X2
  
D
SQL_
GRAPHIC4
X1
D2
  
D
SQL_
VARGRAPHIC4
X1
D2
  
D
SQL_
LONG
VARGRAPHIC4
X1
D2
  
D
SQL_CLOB
D1
X2
  
X
X3
SQL_BLOB
X1
X2
  
D
X3
SQL_DBCLOB
X1
X2
  
D
X3
SQL_
CLOB_
LOCATOR
X1
X2
  
X
D3
SQL_
BLOB_
LOCATOR
X1
X2
  
X
D3
SQL_
DBCLOB_
LOCATOR
X1
X2
  
X
D3
SQL_NUMERIC5
D1
X2
  
X
X
X
X
X
X
X
X
X
X
X
SQL_DECIMAL
D1
X2
  
X
X
X
X
X
X
X
X
X
X
X
SQL_DECFLOAT
D1
X2
  
X
X
X
X
X
X
X
X
X
X
    
SQL_INTEGER
X1
X2
  
X
X
X
X
D
X
X
X
X
X
X
X
SQL_
SMALLINT
X1
X2
  
X
X
D
X
X
X
X
X
X
X
X
SQL_FLOAT
X1
X2
  
X
X
X
X
X
X
X
D
X
X
X
SQL_DOUBLE
X1
X2
  
X
X
X
X
X
X
X
D
X
X
X
SQL_REAL
X1
X2
  
X
X
X
X
X
X
D
X
X
X
X
SQL_BIGINT
X1
X2
  
X
X
X
X
D
D
X
X
X
X
SQL_
TYPE_DATE
X1
X2
  
D
X
X
X
X
SQL_
TYPE_TIME
X1
X2
  
D
X
X
X
X
SQL_
TYPE_
TIMESTAMP
X1
X2
  
X
X
D
D
X
X
SQL_
TYPE_
TIMESTAMP_WITH_ZONE
X1
X2
  
X
X
X
X
D
SQL_ROWID
D1
SQL_XML
X1
X2
X
X
D
Note:
  1. You must bind data to the SQL_C_CHAR data type for Unicode UTF-8 data.
  2. You must bind data with the SQL_C_WCHAR data type for Unicode UCS-2 data.
  3. Data is not converted to LOB locator types; locators represent a data value.

  4. The default C data type conversion for this SQL data type depends upon the encoding scheme your application uses. If your application uses UCS-2 Unicode encoding, the default conversion is to SQL_C_WCHAR. For all other encoding schemes, the default conversion is to SQL_C_DBCHAR.

  5. NUMERIC is a synonym for DECIMAL on Db2 for z/OS®, Db2 server for VSE and VM, and Db2 for Linux®, UNIX, and Windows.

Limits on precision, and scale, as well as truncation and rounding rules are the same as those for Db2 for z/OS, with the following exception; truncation of values to the right of the decimal point for numeric values returns a truncation warning, whereas truncation to the left of the decimal point returns an error. In cases of error, the application should call SQLGetDiagRec() to obtain the SQLSTATE and additional information about the failure. When moving and converting floating point data values between the application and Db2 ODBC, no correspondence is guaranteed to be exact as the values can change in precision and scale.