Oracle9i OLAP Services Concepts and Administration Guide Release 1 (9.0.1) Part Number A88755-01 |
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Localization, 6 of 9
Before you can select the appropriate instance character set, you must assess the requirements for that particular instance. You must take into account the natural language and geographic location of your users and the character sets used by existing data sources and text data. The character set that you choose must be complete enough to represent all the data that users will want to store or manipulate, whether it is originating in the database, an external file, or a persistent analytic workspace. However, it should not be more complete than necessary.
UTF-8 is a variable-width character set encoding that can represent all of the characters included in the Unicode standard, including graphical characters for Japanese, Korean, Chinese, English, Greek, Hebrew, and Russian, using 1, 2, or 3 bytes for each character.
Processing data stored in UTF-8 is slower than processing data stored in either a single-byte character set or a smaller, fixed width, multi-byte character set.
You can improve processing time very quickly and easily just by changing the character set used by OLAP Services. However, if your Oracle database stores data from around the world, or your OLAP applications access NCHAR or NVARCHAR columns, then OLAP Services will need to use UTF-8.
You need to identify a supported character set that is extensive enough to represent all of the data accessed by your OLAP applications, yet no larger than necessary. The basic rule is this:
The OLAP Services instance character set should be the same as the RDBMS database character set whenever possible.
In the following cases, OLAP Services might not have the same character set as the database:
UTF8
.
UTF8
. Note that this data cannot be stored in the database because of incompatibility between the data sets. It can only be stored in the analytic workspace or an external file.
However, in these cases, the database character set can be used:
WE8EBCDIC37
(8-bit EDBDIC, Western European code page 37), then specify WE8ISO8859P1
(8-bit ISO Latin-1). If there is no ASCII equivalent, then specify UTF8
.
To specify the character set, set the NLS_LANG configuration parameter, described in "Specifying the instance character set".
The following table indicates what happens when data moves from one part of the software to another, such as between OLAP Services and a client application or between a text file and OLAP Services.
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