Oracle Globalization Support, NLS_LENGTH_SEMANTICS, Unicode

2012 © Trivadis
BASEL BERN LAUSANNE ZÜRICH DÜSSELDORF FRANKFURT A.M. FREIBURG I.BR. HAMBURG MÜNCHEN STUTTGART WIEN
WELCOME Oracle Globalization Support,
NLS_LENGTH_SEMANTICS,
Unicode and Everything Else
Markus Flechtner
24.12.16
Oracle Globalization Support, NLS_LENGTH_SEMANTICS, Unicode and Everything Else
1

2012 © Trivadis
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About me ..
§ Senior Consultant, Trivadis, Duesseldorf
§ Working with Oracle since 1993
§ Development (Forms, Reports, PL/SQL)
§ Support
§ Database Administration
§ Started at Trivadis in 2008
§ Focus
§ Oracle Real Application Clusters
§ Database Migration
§ Teacher
§ O-AI – Oracle Architecture and Internals
§ O-RAC – Oracle Real Application Clusters
§ O-NF12c DBA – Oracle 12c New Features for DBAs
4
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2012 © Trivadis
AGENDA
1. Character sets & Character Conversion
2. Unicode
3. Oracle Parameters
4. Oracle-Tools: Csscan & csalter
5. Oracle-Tools: Database Migration Assistant for Unicode (DMU)
6. Changing the Character set of an existing Database
7. Change Database and Character set
8. NLS_LENGTH_SEMANTICS & SQL + PL/SQL
9. Recommendations
10.Links & further information
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2012 © Trivadis
Character sets (1)
§ “A character set is just an agreement on what numeric value a symbol
has“, i.e. a mapping table (code point)
§ How to display a numeric value (in the database) as a corresponding character
in the output
§ How to store an input value (e.g. numeric value) in the database (or file etc.)
§ Some well known character sets
§ WE8ISO8859P15 („= WE8ISO8859P1 +€-character + some more“)
§ WE8MSWIN1252
§ AL32UTF8
§ UTF8
§ US7ASCII – not recommended
§ WE8ISO8859P1 (ISO 8859, Page 1, for Western Europe) – not recommended
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2012 © Trivadis
Character sets (2)
§ Oracle 11.2 supports 247 different character sets
§ Oracle database supports different types of character sets
§ SB: single-byte encoding
§ MB: multi-byte encoding
§ FIXED: fixed-width multi-byte encoding
§ ASCII: strict superset of ASCII
§ EURO: Euro symbol supported
§ UDC: User-Defined-Character set (using „Oracle Locale Builder“)
§ See Oracle 11.2 Globalization Support Guide, Appendix A („Locale data“)
for more information
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2012 © Trivadis
Character sets (3) – well known character sets
§ The WE8ISO8859-family
§ WE8ISO8859P1
§ WE8ISO8859P15
§ ..
§ ISO/IEC 8859
§ Differences between ISO8859-1 and -15
§ See http://en.wikipedia.org/wiki/ISO8859 for more information
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2012 © Trivadis
Character Conversion: from client to server (and vice versa)
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WE8MSWIN1252
WE8ISO8859P1
Database Character set =
WE8ISO8859P15
INSERT (‚€‘)
è Converted to
è WE8ISO8859P15
Stored: „€“
SELECT
But the € cannot be displayed
In WE8ISO8859P1!
It‘s all about the correct and compatible setting of database character set,
client OS character set and client Oracle character set!

2012 © Trivadis
Character set- and NLS-information on the database
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SQL> SELECT PROPERTY_VALUE FROM DATABASE_PROPERTIES WHERE PROPERTY_NAME like ’NLS%’;
PROPERTY_NAME PROPERTY_VALUE
------------------------------ -----------------------------------
NLS_LANGUAGE AMERICAN
NLS_TERRITORY AMERICA
NLS_CURRENCY $
NLS_ISO_CURRENCY AMERICA
NLS_NUMERIC_CHARACTERS .,
NLS_CHARACTERSET WE8MSWIN1252
NLS_CALENDAR GREGORIAN
NLS_DATE_FORMAT DD-MON-RR
NLS_DATE_LANGUAGE AMERICAN
NLS_SORT BINARY
NLS_TIME_FORMAT HH.MI.SSXFF AM
NLS_TIMESTAMP_FORMAT DD-MON-RR HH.MI.SSXFF AM
NLS_TIME_TZ_FORMAT HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH.MI.SSXFF AM TZR
NLS_DUAL_CURRENCY $
NLS_COMP BINARY
NLS_LENGTH_SEMANTICS BYTE
NLS_NCHAR_CONV_EXCP FALSE
NLS_NCHAR_CHARACTERSET AL16UTF16
NLS_RDBMS_VERSION 11.2.0.3.0

2012 © Trivadis
AGENDA
2. Unicode
9. Recommendations
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2012 © Trivadis
What's Unicode? - Introduction
§ “Unicode is a computing industry standard for the consistent encoding,
representation and handling of text expressed in most of the world's
writing systems.” (http://en.wikipedia.org/wiki/Unicode)
§ Development started in 1987, current version is Unicode 6.3 (released in
September 2013), representing more than 110.000 characters
§ Universal encoded character set
§ Store information in any language è supports globally used databases
§ AL32UTF8 = variable width (1 – 4 bytes per character)
§ UTF-8 = variable width ( 1 – 3 bytes/character)
§ UTF-16 = fixed width (2 or 4 bytes/character)
§ Oracle supports Unicode since Oracle 8.1
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2012 © Trivadis
Character set AL32UTF8 - Introduction
§ Reminder: “A character set is just an agreement on what numeric
value a symbol has“
§ Supported as database character set since Oracle 9i
§ Recommended character set
§ Check your clients: Old Oracle 8i (or earlier) clients have problems with
AL32UTF8 è use UTF8
§ Characters have variable length (1 – 4 bytes)
è any character other than US7ASCII (A-Z,a-z,0-1 and ./?,*# etc..) needs
more than one byte
è the database may need some more space (csscan will report an
estimation)
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2012 © Trivadis
Character set AL32UTF8 – bytes of storage for different chars
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(from Oracle 11.2 Globalization Support Guide, © Oracle)

2012 © Trivadis
Unicode vs. Classical 8-bit-character set
§ Database 1 – “old fashioned” 8-bit-Character set
§ Database 2 – “modern” Unicode Character set
SQL> SELECT PROPERTY_VALUE FROM DATABASE_PROPERTIES
WHERE PROPERTY_NAME=’NLS_CHARACTERSET';
PROPERTY_VALUE
----------------------------------------------------
AL32UTF8
SQL> INSERT INTO CSDEMO.UMLAUTE VALUES ('äöüÄÖÜß');
SQL> SELECT ZEICHEN,DUMP(ZEICHEN) FROM CSMDEMO.UMLAUTE;
ZEICHEN DUMP(ZEICHEN)
---------- ----------------------------------------------------------------------
äöüÄÖÜß Typ=1 Len=14: 195,164,195,182,195,188,195,132,195,150,195,156,195,159
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SQL> SELECT PROPERTY_VALUE FROM DATABASE_PROPERTIES
WHERE PROPERTY_NAME=‘NLS_CHARACTERSET';
PROPERTY_VALUE
----------------------------------------------------
WE8ISO8859P15
SQL> INSERT INTO CSDEMO.UMLAUTE VALUES ('äöüÄÖÜß');
SQL> SELECT ZEICHEN,DUMP(ZEICHEN) FROM CSMDEMO.UMLAUTE;
ZEICHEN DUMP(ZEICHEN)
---------- ----------------------------------------
äöüÄÖÜß Typ=1 Len=7: 228,246,252,196,214,220,223

2012 © Trivadis
Character set AL32UTF8 – Technical Limits within Oracle
UTF8 | AL32UTF8 | AL16UTF16
(1 to 3 bytes)| (1 to 4 bytes)| (2 bytes)
MIN MAX | MIN MAX | MIN MAX
------------------------------------------------
CHAR 2000 666 | 2000 500 | N/A N/A
VARCHAR2 4000 1333 | 4000 1000 | N/A N/A
------------------------------------------------
NCHAR 2000 666 | N/A N/A | 1000 1000
NVARCHAR2 4000 1333 | N/A N/A | 2000 2000
§ For the national character set, only UT8 and AL16UTF16 are allowed
§ There is still an underlying limit of 4000 Bytes per VARCHAR2 column
è you can store 4000 “a” (single-byte-character) in such a column
§ Every multi-byte character reduces the number of available characters (e.g. you
can store 3997 “a” + 1 “€”, because the EUR-character is a 3 bytes character in
the AL32UTF8 Character set, and 3994 “a” + 2 “€” and so on)
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2012 © Trivadis
AGENDA
2. Unicode
9. Recommendations
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2012 © Trivadis
Oracle Parameters: NLS_LANG (1)
§ „NLS_LANG is used to let Oracle know what character set your client's
OS is USING so that Oracle can do (if needed) conversion from the
client's character set to the database character set.“
§ Character set in NLS_LANG not necessarily equal to DB character set!
§ If both are equal this may be beneficial in terms of performance (OCI)
§ è On typical Western European Windows Clients
§ NLS_LANG=<LANGUAGE>_<TERRITORY>.WE8MSWIN1252
§ è On Unix systems the character set depends on the locale
- Check LC_ALL
- See http://docs.oracle.com/cd/E11882_01/server.112/e10729/applocaledata.htm
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-- Format <Language>_<Territory>.<ClientCharacterSet>
NLS_LANG = GERMAN_SWITZERLAND.AL32UTF8

2012 © Trivadis
Oracle Parameters: NLS_LANG (2)
§ Recommendation on NLS_LANG
§ Set the character set part of NLS_LANG to the character set of the OS, e.g
WE8MSWIN1252 on a Windows client
§ Recommendation on the database character set
§ Choose a character set which is a superset of the character sets of all clients
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2012 © Trivadis
Oracle Parameters: NLS_LENGTH_SEMANTICS (1)
§ Specifies the default length semantics to use for VARCHAR2 and CHAR
table columns
§ Possible values are
§ BYTE (Default)
§ CHAR
§ New hint in the 11.2 documentation:
§ è change the parameter to CHAR on session level only!
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2012 © Trivadis
§ Oracle has changed its’ mind:
§ See the 11.1-documentation
http://docs.oracle.com/cd/B28359_01/server.111/b28298/ch2charset.htm
§ (it’s a “documentation bug”) J
§ But there are MOS-Notes which state “do not set the parameter to
CHAR”, even for 11.1 databases
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2012 © Trivadis
§ Oracle recommends to specify the NLS_LENGTH_SEMANTICS on column
level:
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SQL> CREATE TABLE unicode_demo
(
byte_string VARCHAR2(10 BYTE),
char_string VARCHAR2(10 CHAR)
)
Table created.
SQL> DESCRIBE unicode_demo
Name Null Typ
----------- ---- -----------------
BYTE_STRING VARCHAR2(10 BYTE)
CHAR_STRING VARCHAR2(10)
SQL> INSERT INTO unicode_demo (byte_string) VALUES ('äöüÄÖÜ');
ORA-12899: Value too large for column [..]

2012 © Trivadis
AGENDA
2. Unicode
9. Recommendations
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2012 © Trivadis
Oracle-Tools: Csscan & csalter (1): Introduction
§ CSSCAN
§ Character set Scanner
§ CSALTER
§ Script to change the character set of a database
($ORACLE_HOME/rdbms/admin/csalter.plb)
§ Changes data dictionary only, additional actions for user data may be required
§ Csscan/csalter to be desupported after 11.2
§ Replaced by DMU (Database Migration Assistant to Unicode)
§ Installation of csscan
§ User & Tables created using $ORACLE_HOME/rdbms/admin/csminst.sql
§ Default-User CSMIG (after installation user is locked & password expired)
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2012 © Trivadis
Oracle-Tools: Csscan & csalter (2): csscan: Parameter
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Character set Scanner v2.2 : Release 11.2.0.3.0 - ..
[..]
Keyword Default Prompt Description
---------- ------- ------ -------------------------------------------------
USERID yes username/password
FULL N yes scan entire database
USER yes owner of tables to be scanned
TABLE yes list of tables to scan
COLUMN yes list of columns to scan
EXCLUDE list of tables to exclude from scan
TOCHAR yes new database Character set name
FROMCHAR current database Character set name
TONCHAR new national Character set name
FROMNCHAR current national Character set name
PROCESS 1 yes number of concurrent scan process
LOG scan base file name of report files
[..]
---------- ------- ------ -------------------------------------------------
Scanner terminated successfully.

2012 © Trivadis
Oracle-Tools: Csscan & csalter (3)
§ How to find out if the database contains characters which
do not belong to the database character set (and therefore
can not be converted to AL32UTF8 or any other character
set)?
§ èset FROMCHAR=TOCHAR=current character set (sic!)
§ (in theory) running csscan with TOCHAR=AL32UTF8 makes
no sense, because AL32UTF8 contains all characters J
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oracle> csscan userid='"/ as sysdba"' full=y
fromchar=WE8ISO8859P15 tochar=WE8ISO8859P15 ARRAY=1024000
LOG=/tmp/csscan_source.log PROCESS=8

2012 © Trivadis
Oracle-Tools: Csscan & csalter (4): Summary Report
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[Data Dictionary Conversion Summary]
Datatype Changeless Convertible Truncation Lossy
--------------------- ---------------- ---------------- ---------------- ----------------
VARCHAR2 1.778.335 0 0 0
CHAR 94 0 0 0
LONG 128.565 0 0 0
CLOB 22.072 0 0 0
VARRAY 19.812 0 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
Total 1.948.878 0 0 0
Total in percentage 100,000% 0,000% 0,000% 0,000%
The data dictionary can be safely migrated using the CSALTER script
[Application Data Conversion Summary]
Datatype Changeless Convertible Truncation Lossy
--------------------- ---------------- ---------------- ---------------- ----------------
VARCHAR2 682.846.037 0 0 872.321
CHAR 134.119.259 0 0 0
LONG 36.528 0 0 0
CLOB 0 0 0 0
VARRAY 0 0 0 0
--------------------- ---------------- ---------------- ---------------- ----------------
Total 817.001.824 0 0 872.321
Total in percentage 99,893% 0,000% 0,000% 0,107%

2012 © Trivadis
Oracle-Tools: Csscan & csalter (5): csscan - Results
§ Changeless
§ OK, no more steps required
§ Simply run „csalter“ to change the data dictionary
§ Convertible
§ Data has to be converted between the character sets (due to a different character
mapping)
è export/import
§ Lossy data
§ Existing database contains data which cannot be converted to new character set
§ è correct the data so that it can be converted, otherwise csalter will fail!
§ Truncation
§ Modify column length (if possible)
§ Shorten data if necessary or switch to CLOB
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2012 © Trivadis
Oracle-Tools: Csscan & csalter (6): csscan - Truncation
§ Csscan reports the „Max Post Conversion Data Size” (in Byte!)
è there is no problem with a size less than 4000 Byte (for VARCHAR2)
resp. 2000 (CHAR).
§ Otherwise csscan will report these columns
§ è you have to take care for these columns (shorten data in a senseful
way or migrate to CLOB)
§ è otherwise you will loose some information L
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2012 © Trivadis
Oracle-Tools: Csscan & csalter (7): csscan – Lossy Data
§ “Lossy” data is data which cannot be converted to the target character
set
è in most cases result of an invalid NLS_LANG setting on the client
è Data Cleanup is required
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User : DEMO
Table : COST_ID
Column: DESCRIPTION
Type : VARCHAR2(80)
Number of Exceptions : 13
Max Post Conversion Data Size: 81
ROWID Exception Type Data(first 30 bytes)
------------------ ------------------ -----------------------------
AAAPYvAANAAADOfAAr lossy conversion GEBŽUDE W1 (BšROGEBŽUDE)
AAAPYvAANAAADOPAAs lossy conversion FIRMENANGEH(tm)RIGEN-NEUFAHRZE
AAAPYvAANAAADOPABB lossy conversion GEBŽUDE FMI
AAAPYvAANAAADOvAAP lossy conversion EINFšHRUNG EURO
AAAPYvAANAAADOvABN lossy conversion OBERFLŽCHENVEREDELUNG (KOPF-KS
AAAPYvAANAAADQGABJ lossy conversion BENUTZERSERVICE, CAD-SERVICE,

2012 © Trivadis
Oracle-Tools: Csscan & csalter (8): Data Cleanup Script
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SQL> set serveroutput on
SQL> BEGIN
FOR c_rec IN
(SELECT owner_name,table_name,column_name,data_rowid
FROM csmig.csmv$errors WHERE error_type='DATA_LOSS')
LOOP
sql_statement := 'SELECT '||c_rec.column_name||' from
'||c_rec.owner_name||'.'||c_rec.table_name||' where
rowid='||chr(39)||c_rec.data_rowid||chr(39);
execute immediate sql_statement into old_value;
dbms_output.put_line
('UPDATE '||c_rec.owner_name||'.'||c_rec.table_name||
' SET '||c_rec.column_name||'='||chr(39)||old_value||chr(39)||
' where ROWID='||chr(39)||c_rec.data_rowid||chr(39)||';');
END LOOP;
END;
/
è Results look like
[..]
UPDATE OWNER.TABELLE SET SPALTE='Durchf?hrung' WHERE ROWID=' … ' ;

2012 © Trivadis
Oracle-Tools: Csscan & csalter (9): csalter
§ Changes the data dictionary only, no user data
§ Use it only if you have “changeless” data only in the database (otherwise
csalter will fail)
§ Csalter runs in restricted mode only
§ If you have “convertible” columns in the database, you can run csalter +
export/import (on table or user level) to convert the data
§ è if you have “convertible” data in your database, switching to a new
database may be the better option
§ è old database remains as a fallback solution
§ è reorganization etc. possible
§ In most cases csalter will fail, so the recommendation is: do not use it!
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2012 © Trivadis
Oracle-Tools: Csscan & csalter (10): csalter
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SQL> @@csalter.plb
0 rows created.
Function created.
Function created.
Procedure created.
This script will update the content of the Oracle Data Dictionary.
Please ensure you have a full backup before initiating this procedure.
Would you like to proceed (Y/N)?Y
old 6: if (UPPER('&conf') <> 'Y') then
new 6: if (UPPER('Y') <> 'Y') then
Checking data validility...
begin converting system objects
PL/SQL procedure successfully completed.
Alter the database character set...
CSALTER operation completed, please restart database
PL/SQL procedure successfully completed.
0 rows deleted.
Function dropped.
Function dropped.
Procedure dropped.

2012 © Trivadis
AGENDA
2. Unicode
9. Recommendations
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2012 © Trivadis
Oracle-Tools: DMU (1) - Overview
§ DMU = Database Migration Assistant for Unicode, current version: 1.2
§ JAVA-based GUI-tool, requires J2SE SDK
§ DMU can convert/migrate/change the NLS_CHARACTERSET to
AL32UTF8/UTF8 for a database
§ Successor of csscan/csalter
§ New features (compared to csscan/csalter)
§ Aggregates all tools in UI
§ Extended analysis features
§ Automation of modification and conversion tasks
§ Download via OTN or MOS:
§ http://www.oracle.com/technetwork/products/globalization/dmu/overview/index-
330958.html
§ MOS: Patch 13262762
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2012 © Trivadis
Oracle-Tools: DMU (2) - Installation
§ Database Server
§ A server side patch (9825461) is required
§ The patch is included in 11.2.0.3 (and up)
§ Patch is not available for all versions (e.g. use of DMU with 11.2.0.2.4 or
10.2.0.5.4 is not supported) è csscan/csalter as “Fallback”
§ Database
§ Run $ORACLE_HOME/rdbms/admin/prvtdumi.plb to install the package
SYS.DBMS_DUMA_INTERNAL
§ Client
§ J2SE SDK 6 is required
§ See MOS-Note 1272374.1 for more information
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2012 © Trivadis
Oracle-Tools: DMU (3) - Workflow
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2012 © Trivadis
Oracle-Tools: DMU (4) – Create Repository
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2012 © Trivadis
Oracle-Tools: DMU (5) – Scan the database
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2012 © Trivadis
Oracle-Tools: DMU (6) – Solve issues
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2012 © Trivadis
Oracle-Tools: DMU (7) – “Bulk Cleansing”
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2012 © Trivadis
Oracle-Tools: DMU (9) – How does DMU do the conversion?
1. Put the database into restricted mode.
2. Disable various job queue processes.
3. Drop or disable selected indexes.
4. Disable selected triggers and constraints.
5. Convert the data in user tables and in selected data dictionary tables to Unicode.
6. Convert CLOB columns in the data dictionary.
7. Issue the ALTER DATABASE Character set statement.
8. Enable triggers and constraints; and re-create indexes and constraints.
9. Restore the database instance parameters.
The conversion of a table is performed either by updating its columns with an UPDATE
statement or by converting the columns while re-creating the table using the CREATE TABLE
AS SELECT statement. The re-creation of a table is faster than an update if most of the table
rows must be converted.
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SQL> UPDATE <col> SET <col>=SYS_OP_CSCONV(<col>, 'AL32UTF8');

2012 © Trivadis
AGENDA
2. Unicode
6. Changing the Character set of an existing Database (csscan/csalter)
9. Recommendations
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2012 © Trivadis
Changing the Character set of an existing Database (1)
§ Don’t forget to backup your database before changing the
Character set!
§ Prepare for csscan
§ Run csscan
§ Evaluate output
§ Data Cleanup
§ Run csalter (remember the backup beforehand)
§ If you have convertible columns or CLOBS: run (partial) export/import to
migrate user data
§ Update Statistics
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2012 © Trivadis
Change Database & Character set (1) - Preparation
§ Prepare for csscan
§ Run csscan
§ Evaluate output
§ Data Cleanup
§ Create empty tables in new database
§ With correct CREATE scripts (<column> VARCHAR2 (xxx CHAR))
§ (or) Adjust column length / semantics after creation
§ You can modify the length semantics in the source database, too. In
this case you don’t have to create the tables before importing them
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SQL> ALTER TABLE demo_table
2 MODIFY (demo_column VARCHAR2(20 CHAR));

2012 © Trivadis
Change Database & Character set (2) – Data Transfer
§ Option 1:
1. Datapump Export
2. Datapump Import
(with TABLE_EXISTS_ACTION=TRUNCATE|APPEND!)
§ Option 2:
§ Streams (è “near-zero-downtime” possible)
§ Option 3:
§ Own methods (e.g. INSERT INTO tab@newdb SELECT * from
tab@olddb;
§ Or
§ Golden Gate, Quest Shareplex etc.
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2012 © Trivadis
NLS_LENGTH_SEMANTICS & SQL + PL/SQL
§ Take care for functions
§ Don’t forget the NLS_LENGTH_SEMANTICS in PL/SQL-code
§ Additional changes to application code may be required (see
Globalization Support Guide for more information)
§ Don’t forget to test the application with the Unicode database!
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Refers to characters of
the input character set
Refers to bytes Refers to Unicode
characters
LENGTH LENGTHB LENGTHC
INSTR INSTRB INSTRC
SUBSTR SUBSTRB SUBSTRC
...

2012 © Trivadis
Recommendations – summarized (1) – Parameter
§ Parameter NLS_LANG
§ Set the character set part of NLS_LANG to the character set of the OS
- On Windows: check your environment for the ASCII codepage, choose the
appropriate character set, e.g. WE8MSWIN1252 (see MOS-Note 179133.1
for details)
- On Unix: check your locale setting (“locale –a”), see MOS-Note 264157.1
for details
§ Parameter NLS_LENGTH_SEMANTICS
§ On instance level: BYTE
§ On column level (in DDL statements): CHAR
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2012 © Trivadis
Recommendations – summarized (2) – DB Character set
§ Database character set
§ Choose a character set which is a superset of the character sets of all clients
(see Oracle Globalization Support Guide 11.2, Apendix A) for details)
§ think about future requirements
§ Oracle recommends using Unicode for all new system deployments (Oracle
11.2 Globalization Support Guide, Chapter 2 “Choosing a character set”)
§ If you have to store Unicode data, choose a Unicode database character set
§ National character set (for NCHAR, NVARCHAR2, NCLOB)
§ As Oracle supports Unicode as a database character set, the “N-datatypes”
should not be used (this simplifies application development)
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2012 © Trivadis
Recommendations – summarized (3) – Character set Migration
§ Migrating the character set of a database to Unicode
§ Check your existing data carefully and change data which cannot be
converted
§ Recommended: create a new database with character set AL32UTF8 and
transfer the data to the new database using e.g. Datapump
- è old database remains as a fallback solution
- è reorganization possible
- è Near-Zero-Downtime migration possible with Oracle Streams
§ Change the character set of an existing database if you have
„changeless“ columns only or if diskspace is an issue
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2012 © Trivadis
Recommendations – summarized (4) - Tools
§ Csscan/csalter
§ To be desupported after 11.2 (MOS-Note 1418321.1)
§ Fallback solution if DMU cannot be used
§ In most cases only csscan is used (in order to analyze the existing data)
§ Database Migration Assistant for Unicode (DMU)
§ Successor of csscan/csalter
§ Default tool for 12c
§ Patch 9825461 required (included in 11.2.0.3 and higher, but not available for
all database versions below 11.2.0.3)
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2012 © Trivadis
Links & Further Information (1)
§ Oracle Documentation
§ Oracle® Database Globalization Support Guide 11.2
§ Unicode in general
§ http://www.unicode.org/versions/Unicode6.1.0/
§ http://www.fileformat.info/info/unicode/utf8.htm
§ Database Migration Assistant for Unicode
§ http://www.oracle.com/technetwork/products/globalization/dmu/overview/index.html
§ Near-Zero Downtime Migration Model with DMU & Oracle Streams
- http://www.oracle.com/technetwork/products/globalization/dmu/learnmore/nzd-
migration-524223.html
§ Misc
§ Oracle Whitepaper „Character Set Migration – Best Practices“
§ http://www.oracle-base.com/articles/9i/character-semantics-and-globalization-9i.php
§ http://www.oracle-base.com/articles/10g/character-set-migration.php
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2012 © Trivadis
Links & Further Information (2)
§ My Oracle Support Notes
§ 144808.1 - Examples and limits of BYTE and CHAR semantics usage
(NLS_LENGTH_SEMANTICS)
§ 1272374.1 - The Database Migration Assistant for Unicode (DMU) Tool
§ 276914.1 - The National Character set ( NLS_NCHAR_Character set ) in Oracle 9i, 10g
and 11g
§ 225912.1 - Changing the Database Character Set ( NLS_Character set )
§ 69518.1 - Storing and Checking Character Codepoints in an UTF8/AL32UTF8 (Unicode)
database
§ 788156.1 - AL32UTF8 / UTF8 (Unicode) Database Character set Implications
§ 745809.1 - Installing and configuring Csscan in 10g and 11g (Database Character set
Scanner)
§ 444701.1 - Csscan output explained
§ 158577.1 - NLS_LANG Explained (How does Client-Server Character Conversion Work?)
§ 264157.1 - The correct NLS_LANG setting in Unix Environments
§ 179133.1 - The correct NLS_LANG in a Windows Environment
§ 1522722.1 - Known Issues With The DMU Tool version 1.2
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2012 © Trivadis
BASEL BERN LAUSANNE ZÜRICH DÜSSELDORF FRANKFURT A.M. FREIBURG I.BR. HAMBURG MÜNCHEN STUTTGART WIEN
Thank you
for your attention
Trivadis GmbH
Markus Flechtner
Werdener Straße 4
40227 Düsseldorf
Tel. +49-211-5866 6470
Fax +49-211-5866 6471
Markus.Flechtner@trivadis.com
www.trivadis.com
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Oracle Globalization Support, NLS_LENGTH_SEMANTICS, Unicode

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