I was reading an instruction manual and it was mentioned to check the nsl character set. Can someone please tell me what is 'NSL' character and why do we need to set 'NSL' character in DB?
When your computer process characters, they use numeric codes instead of the graphical representation of the character. For example, when the database stores the letter A, it actually stores a numeric code that is interpreted by software as the letter. These numeric codes are especially important in a global environment because of the potential need to convert data between different character sets.
Basically we use UTF8 and UTF16 most cases. Refer documentation for further details
Query current setting
SELECT value$ FROM sys.props$ WHERE name = 'NLS_CHARACTERSET' ;
SELECT * FROM NLS_DATABASE_PARAMETERS
# Session level
ALTER SESSION SET NLS_CHARACTERSET = WE8ISO8859P1
# DB level
ALTER DATABASE CHARACTER SET <new_character_set_name>;
Refer:http://docs.oracle.com/cd/B10501_01/server.920/a96529/ch10.htm
Related
I need to update value in one table, which is having special character.
Below is the Update Query I have Executed:
UPDATE TABLE_X
SET DISPLAY_NAME = 'AC¦', NATIVE_IDENTITY='AC¦'
WHERE ID='idNumber'
Special Character "¦" is not getting updated in Oracle.
I have already tried below approaches:
Checked the character set being used in Oracle using below query
select * from nls_database_parameters where parameter='NLS_CHARACTERSET';
It is having "US7ASCII" Character set.
I have tried to see if any of the character set will help using below query
SELECT CONVERT('¦ ', 'ASCII') FROM DUAL;
I have tried below different encoding:
WE8MSWIN1252
AL32UTF8
BINARY - this one is giving error "ORA-01482: unsupported character set"
Before Changing the character set in DB i wanted to try out 'CONVERT' function from Oracle, but above mentioned character set is either returning "Block Symbol" or "QuestionMark � " Symbol.
Any idea how can I incorporate this special symbol in DB?
Assuming that the character in question is not part of the US7ASCII character set, which it does not appear to be unless you want to replace it with the ASCII vertical bar character |, you can't validly store the character in a VARCHAR2 column in the database.
You can change the database character set to a character set that supports all the characters you want to represent
You can change the data type of the column to NVARCHAR2 assuming your national character set is UTF-16 which it would normally be.
You can store a binary representation of the character in some character set you know in a RAW column and convert back from the binary representation in your application logic.
I would prefer changing the database character set but that is potentially a significant change.
I would like to know the difference between
NLS_NCHAR_CHARACTERSET and NLS_CHARACTERSET settings in Oracle?
From my understanding, NLS_NCHAR_CHARACTERSET is for NVARCHAR data types
and for NLS_CHARACTERSET would be for VARCHAR2 data types.
I tried to test this on my development server which my current settings for CHARACTERSET are as the following :
PARAMETER VALUE
------------------------------ ----------------------------------------
NLS_NCHAR_CHARACTERSET AL16UTF16
NLS_NUMERIC_CHARACTERS .,
NLS_CHARACTERSET US7ASCII
Then I inserted some Chinese character values into the database. I inserted the characters into a table called data_<seqno> and updated the column for ADDRESS and ADDRESS_2 which are VARCHAR2 columns. Right from my understanding with the current setting for NLS_CHARACTERSET US7ASCII, Chinese characters should not be supported but it is still showing in the database. Does NLS_NCHAR_CHARACTERSET take precedence over this?
Thank You.
In general all your points are correct. NLS_NCHAR_CHARACTERSET defines the character set for NVARCHAR2, et. al. columns whereas NLS_CHARACTERSET is used for VARCHAR2.
Why is it possible that you see Chinese characters with US7ASCII?
The reason is, your database character set and your client character set (i.e. see NLS_LANG value) are both US7ASCII. Your database uses US7ASCII and it "thinks" also the client sends data using US7ASCII. Thus it does not make any conversion of the strings, the data are transferred bit-by-bit from client to server and vice versa.
Due to that fact you can use characters which are actually not supported by US7ASCII. Be aware, in case your client uses a different character set (e.g. when you use ODP.NET Managed Driver in an Windows application) the data will be rubbish! Also if you would consider a database character set migration you have the same issue.
Another note: I don't think you would get the same behavior with other character sets, e.g. if your database and your client both would use WE8ISO8859P1 for example. Also be aware that you actually have wrong configuration. Your database uses character set US7ASCII, your NLS_LANG value is also US7ASCII (most likely it is not set at all and Oracle defaults it to US7ASCII) but the real character set of SQL*Plus, resp. your cmd.exe terminal is most likely CP950 or CP936.
If you like to set everything properly you can either set your environment variable NLS_LANG=.ZHT16MSWIN950 (CP936 seems to be not supported by Oracle) or change your codepage before running sqlplus.exe with command chcp 437. With this proper settings you will not see any Chinese characters as you probably would have expected.
I have data which contains special characters like à ç è etc..
I am trying to insert the data into tables having these characters. Data gets inserted without any issues but these characters are replaced with with ?/?? when stored in tables
How should I resolve this issue?I want to store these characters in my tables.
Is it related to NLS parameters?
Currently the NLS characterset is having AL32UTF8 as seen from V$Nls_parameters table.
Is there any specific table/column to be checked ? Or is it something at the database settings ?
Kindly advise.
Thank in advance
From the comments: It is not required that column must be NVARCHAR (resp. NVARCHAR2), because your database character set is AL32UTF8 which supports any Unicode character.
Set your NLS_LANG variable to AMERICAN_AMERICA.AL32UTF8 before you launch your SQL*Plus. You may change the language and/or territory to your own preferences.
Ensure you select a font which is able to display the special characters.
Note, client character set AL32UTF8 is determined by your local LANG variable (i.e. en_US.UTF-8), not by the database character set.
Check also this answer for more information: OdbcConnection returning Chinese Characters as "?"
I do find a problem with enconding of characters into Oracle
They are two inverted interrogation characters coming from imported data.
How can i search for two inverted characters into Oracle so i can see how many lines have this problem ?
I assume by "inverted interrogation character" you mean character ¿.
There are two possibilities:
Character ¿ is actually stored in your database, because your database character set (check with SELECT * FROM V$NLS_PARAMETERS WHERE PARAMETER LIKE '%CHARACTERSET') is not capable to support special characters you tried to import.
You can find affected rows with SELECT * FROM TABLE_NAME WHERE REGEXP_LIKE(COL_NAME, '¿');
Your client (e.g. SQL*Plus) is not able to display the special character and substitute those by placeholder ¿. In this case set your NLS_LANG value properly, see this answer for more details.
Unfortunately you did not tell us how you imported your data nor any of your characters sets. Thus I cannot provide you a guideline to set NLS_LANG properly.
I am running following query in SQL*Plus
CREATE TABLE tbl_audit_trail (
id NUMBER(11) NOT NULL,
old_value varchar2(255) NOT NULL,
new_value varchar2(255) NOT NULL,
action varchar2(20) CHARACTER SET latin1 NOT NULL,
model varchar2(255) CHARACTER SET latin1 NOT NULL,
field varchar2(64) CHARACTER SET latin1 NOT NULL,
stamp timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
user_id NUMBER(11) NOT NULL,
model_id varchar2(65) CHARACTER SET latin1 NOT NULL,
PRIMARY KEY (id),
KEY idx_action (action)
);
I am getting following error:
action varchar2(20) CHARACTER SET latin1 NOT NULL,
*
ERROR at line 5:
ORA-00907: missing right parenthesis
Can you suggest what am I missing?
The simple answer is that, unlike MySQL, character sets can't be defined at column (or table) level. Latin1 is not a valid Oracle character set either.
Character sets are consistent across the database and will have been specified when you created the database. You can find your character by querying NLS_DATABASE_PARAMETERS,
select value
from nls_database_parameters
where parameter = 'NLS_CHARACTERSET'
The full list of possible character sets is available for 11g r2 and for 9i or you can query V$NLS_VALID_VALUES.
It is possible to use the ALTER SESSION statement to set the NLS_LANGUAGE or the NLS_TERRITORY, but unfortunately you can't do this for the character set. I believe this is because altering the language changes how Oracle would display the stored data whereas changing the character set would change how Oracle stores the data.
When displaying the data, you can of course specify the required character set in whichever client you're using.
Character set migration is not a trivial task and should not be done lightly.
On a slight side note why are you trying to use Latin 1? It would be more normal to set up a new database in something like UTF-8 (otherwise known as AL32UTF8 - don't use UTF8) or UTF-16 so that you can store multi-byte data effectively. Even if you don't need it now it's wise to attempt - no guarantees in life - to future proof your database with no need to migrate in the future.
If you're looking to specify differing character sets for different columns in a database then the better option would be to determine if this requirement is really necessary and to try to remove it. If it is definitely necessary1 then your best bet might be to use a character set that is a superset of all potential character sets. Then, have some sort of check constraint that limits the column to specific hex values. I would not recommend doing this at all, the potential for mistakes to creep in is massive and it's extremely complex. Furthermore, different character sets render different hex values differently. This, in turn, means that you need to enforce that a column is rendered in a specific character, which is impossible as it falls outside the scope of the database.
1. I'd be interested to know the situation
According to provided DDL statement it's some need to use 2 character sets. The implementation of this functionality in Oracle is different from MySQL and done with n* data types like nvarchar2, nchar... Latin1 is similar to some Western European character set that might be default. So you able to define for example "Latin1" (WE**) and some Unicode (UTF8..).
The NVARCHAR2 datatype was introduced by Oracle for databases that want to use Unicode for some columns while keeping another character set for the rest of the database (which uses VARCHAR2). The NVARCHAR2 is a Unicode-only datatype.
The reason you want to use NVARCHAR2 might be that your DB uses a non-Unicode character and you still want to be able to store Unicode data for some columns.
Columns in your example would be able to store the same data, however the byte storage will be different.