Encoding scenarios for retrieval of XML data with implicit serialization

The target encoding and application code page can affect data conversion, truncation due to expansion, and internal encoding during XML data retrieval with implicit serialization.

The following examples demonstrate these interactions.

Only scenario 1 and scenario 2 apply to Java™ applications, because the application code page for Java applications is always Unicode. In general, code page conversion is not a problem for Java applications.

Scenario 1

Encoding source	Value
Target data encoding	UTF-8 Unicode
Target application data type	Binary
Application code page	Not applicable

Example output statements:

SELECT XMLCOL FROM T1

Character conversion: None.

Data loss: None.

Truncation due to expansion: None.

Internal encoding in the textual XML data: For applications other than Java applications, the data is prefixed by the following XML declaration:

<?xml version="1.0" encoding="UTF-8" ?>

For Java applications, no encoding declaration is added, unless you cast the data as the com.ibm.db2.jcc.DB2Xml type, and use a getDB2Xmlxxx method to retrieve the data. The declaration that is added depends on the getDB2Xmlxxx that you use.

Scenario 2

Encoding source	Value
Target data encoding	UTF-16 Unicode
Target application data type	Graphic
Application code page	CCSID 1208

Example output statements:

SELECT XMLCOL FROM T1

Character conversion: Data is converted from UTF-8 to UTF-16.

Data loss: None.

Truncation due to expansion: Truncation can occur during conversion from UTF-8 to UTF-16, due to expansion.

Internal encoding in the textual XML data: For applications other than Java applications, the data is prefixed by a UTF-16 Byte Order Mark (BOM) and the following XML declaration:

<?xml version="1.0" encoding="UTF-16" ?>

Scenario 3

Encoding source	Value
Target data encoding	ISO-8859-1 data
Target application data type	Character
Application code page	819

Example output statements:

SELECT XMLCOL FROM T1

Character conversion: Data is converted from UTF-8 to CCSID 819.

Data loss: Possible data loss. Some UTF-8 characters cannot be represented in CCSID 819. The Db2 database system generates an error.

Truncation due to expansion: None.

Internal encoding in the textual XML data: The data is prefixed by the following XML declaration:

<?xml version="1.0" encoding="ISO-8859-1" ?>

Scenario 4

Encoding source	Value
Target data encoding	Windows-31J data (superset of Shift_JIS)
Target application data type	Graphic
Application code page	943

Example output statements:

SELECT XMLCOL FROM T1

Character conversion: Data is converted from UTF-8 to CCSID 943.

Data loss: Possible data loss. Some UTF-8 characters cannot be represented in CCSID 943. The Db2 database system generates an error.

Truncation due to expansion: Truncation can occur during conversion from UTF-8 to CCSID 943 due to expansion.

Internal encoding in the textual XML data: The data is prefixed by the following XML declaration:

<?xml version="1.0" encoding="Windows-31J" ?>