Char, varchar and varchar2

What is the difference between char, varchar and varchar2 ???

Apart from reading the documentation where it's clearly available.
In short:
char : fixed length strings (strings are auto right padded with spaces to the specified size)
varchar : reserved for future use (although presently acts the same as varchar2)
varchar2 : variable length strings

Similar Messages

Char(1) and varchar2(1)

Can some one tell me the major difference between CHAR(1) and VARCHAR2(1), I need to use flag column of 1 byte.
Which is best for use

adam wrote:
at the same time almost never marking a question as resolved
I am not satisfied the given answers that is the reason for unmarked the answer.If i get the right answer i should mark as the right answer.
you should know one thing i am not expert in oracle database .....
what is mean by doc questions ?
"doc questions" (short for "documentation questions) are questions that can easily be answered by consulting the docs (documentation)
Learning how to look things up in the documentation is time well spent investing in your career. To that end, you should drop everything else you are doing and do the following:
Go to tahiti.oracle.com.
Drill down to your product and version.
BOOKMARK THAT LOCATION
Spend a few minutes just getting familiar with what is available here. Take special note of the "books" and "search" tabs. Under the "books" tab you will find the complete documentation library.
Spend a few minutes just getting familiar with what kind of documentation is available there by simply browsing the titles under the "Books" tab.
Open the Reference Manual and spend a few minutes looking through the table of contents to get familiar with what kind of information is available there.
Do the same with the SQL Reference Manual.
Do the same with the Utilities manual.
You don't have to read the above in depth. They are reference manuals. Just get familiar with what is there to be referenced. Ninety percent of the questions asked on this forum can be answered in less than 5 minutes by simply searching one of the above manuals.
Then set yourself a plan to dig deeper.
- Read a chapter a day from the Concepts Manual.
- Take a look in your alert log. One of the first things listed at startup is the initialization parms with non-default values. Read up on each one of them (listed in your alert log) in the Reference Manual.
- Take a look at your listener.ora, tnsnames.ora, and sqlnet.ora files. Go to the Network Administrators manual and read up on everything you see in those files.
- When you have finished reading the Concepts Manual, do it again.
Give a man a fish and he eats for a day. Teach a man to fish and he eats for a lifetime.
Edited by: adam on Aug 31, 2012 4:03 AM
Edited by: adam on Aug 31, 2012 4:45 AM

Database Adapter Merge with char/varchar primary key

Hi guys,
It seems as though merge statements in BPEL database adapters do not work if the primary key of the table contains a char/varchar. This is in Jdeveloper 10.1.3.4.0
If I create the table below:
create table test_merge (
id        number primary key,
text      varchar2(255)
);Then the merge operation will update and insert as expected. However, if I create the same table but with id as a char/varchar, then the merge statement will never update.
It seems like it never finds a record with the same id (if it is a char/varchar), and always attempts to insert, which results in unique key constraint errors for the primary key column.
Has anyone else encountered this issue and found a way to get the merge statement to work correctly? I can obviously perform the select myself, and then conditionally update/insert, but I would prefer the merge to work as expected.
Thanks

After investigating further, it seems that even a database adapter select is not working correctly. Consider the following table:
create table test_merge (
id        varchar2(255) primary key,
text      varchar2(255)
);And I have inserted a record with id = "1" and text="abc"
If I create a BPEL process and add a database adapter (with only the select checkbox ticked) with the following SQL:
SELECT ID, TEXT FROM TEST_MERGE WHERE (ID = #id)If I invoke this adapter, passing in "1" as the id, then a record is returned, with the correct text (i.e. "abc") BUT the id returned is "-9900000000000000000000000000"
Can anyone explain why this is happening?

Varchar vs varchar2

Are there any major differences between varchar and varchar2?

From the SQL Reference Guide:
 
"The VARCHAR datatype is currently synonymous with the VARCHAR2 datatype.
Oracle recommends that you use VARCHAR2 rather than VARCHAR. In the future,
VARCHAR might be defined as a separate datatype used for variable-length character strings compared with different comparison semantics."

Difference between CHAR and VARCHAR2 datatype

Difference between CHAR and VARCHAR2 datatype
CHAR datatype
If you have an employee name column with size 10; ename CHAR(10) and If a column value 'JOHN' is inserted, 6 empty spaces will be inserted to the right of the value. If this was a VARCHAR column; ename VARCHAR2(10). How would it handle the column value 'JOHN' ?

The CHAR datatype stores fixed-length character strings, and Oracle compares CHAR values using blank-padded comparison semantics.
Where as the VARCHAR2 datatype stores variable-length character strings, and Oracle compares VARCHAR2 values using nonpadded comparison semantics.
This is important when comparing or joining on the columns having these datatypes;
SQL*Plus: Release 10.2.0.1.0 - Production on Pzt Au 6 09:16:45 2007
Copyright (c) 1982, 2005, Oracle. All rights reserved.
SQL> conn hr/hr
Connected.
SQL> set serveroutput on
SQL> DECLARE
2 last_name1 VARCHAR2(10) := 'TONGUC';
3 last_name2 CHAR(10) := 'TONGUC';
4 BEGIN
5 IF last_name1 = last_name2 THEN
6 DBMS_OUTPUT.PUT_LINE ( '-' || last_name1 || '- is equal to -' || last_name2
|| '-');
7 ELSE
8 DBMS_OUTPUT.PUT_LINE ( '-' || last_name1 || '- is NOT equal to -' || last_n
ame2 || '-');
9 END IF;
10 END;
11 /
-TONGUC- is NOT equal to -TONGUC -
PL/SQL procedure successfully completed.
SQL> DECLARE
2 last_name1 CHAR(6) := 'TONGUC';
3 last_name2 CHAR(10) := 'TONGUC';
4 BEGIN
5 IF last_name1 = last_name2 THEN
6 DBMS_OUTPUT.PUT_LINE ( '-' || last_name1 || '- is equal to -' || last_name2
|| '-');
7 ELSE
8 DBMS_OUTPUT.PUT_LINE ( '-' || last_name1 || '- is NOT equal to -' || last_n
ame2 || '-');
9 END IF;
10 END;
11 /
-TONGUC- is equal to -TONGUC -
PL/SQL procedure successfully completed.
Also you may want to read related asktom thread - "Char Vs Varchar" http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:1542606219593
and http://tahitiviews.blogspot.com/2007/05/less-is-more-more-or-less.html
Best regards.

Difference between nvarchar2( 10) and varchar2( 10 char)

Hi ,
I had to enhance my application's DB to support unicode data entries(Multilingual data entries) and retrieval. I want to know the basic difference between the following data type decalrations:
nvarchar2( 10) and varchar2( 10 char)
Can any one suggest me which would be a optimum choice?
regards,
Siddarth

Yes, you are almost correct.
Can you read Japanese Character ? (There is no need to understand Japanese words meanings).
Are you ready? Let's go!
SQL> create table tab_size(col varchar(3));
Table created.
SQL> insert into tab_size values ('abc');
1 row created.
SQL> insert into tab_size values ('abcd');
insert into tab_size values ('abcd')
ERROR at line 1:
ORA-12899: value too large for column "USHI"."TAB_SIZE"."COL" (actual: 4, maximum: 3)
SQL> insert into tab_size values('ｱｲｳ'); /* This is 3 characters (3byte) */
1 row created.
SQL> insert into tab_size values('ｱｲｳｴ'); /* This is 4 characters (4byte) */
insert into tab_size values('ｱｲｳｴ')
ERROR at line 1:
ORA-12899: value too large for column "USHI"."TAB_SIZE"."COL" (actual: 4, maximum: 3)
SQL> insert into tab_size values ('あ'); /* This is 1 character (2bytes) */
1 row created.
SQL> insert into tab_size values ('あい'); /* This is 2 characters (4bytes) */
insert into tab_size values ('あい')
ERROR at line 1:
ORA-12899: value too large for column "USHI"."TAB_SIZE"."COL" (actual: 4, maximum: 3)
SQL> insert into tab_size values ('aあ'); /* This is 2 characters (3bytes) */
1 row created.
SQL> insert into tab_size values ('abあ'); /* This is 3 characters (4bytes) */
insert into tab_size values ('abあ')
ERROR at line 1:
ORA-12899: value too large for column "USHI"."TAB_SIZE"."COL" (actual: 4, maximum: 3)
SQL> drop table tab_size;
Table dropped.
SQL> create table tab_char (col varchar2(3 char));
Table created.
SQL> insert into tab_char values ('abc');
1 row created.
SQL> insert into tab_char values ('abcd');
insert into tab_char values ('abcd')
ERROR at line 1:
ORA-12899: value too large for column "USHI"."TAB_CHAR"."COL" (actual: 4,
maximum: 3)
SQL> insert into tab_char values ('あいう'); /* This is 3 characters (6bytes) */
1 row created.
SQL> insert into tab_char values ('あいうえ'); /* This is 4 characters (8bytes) */
insert into tab_char values ('あいうえ')
ERROR at line 1:
ORA-12899: value too large for column "USHI"."TAB_CHAR"."COL" (actual: 4, maximum: 3)
SQL> insert into tab_char values ('aあい'); /* This is 3 characters (5bytes) */
1 row created.
SQL> insert into tab_char values ('abあい'); /* This is 4 characters (6bytes) */
insert into tab_char values ('abあい')
ERROR at line 1:
ORA-12899: value too large for column "USHI"."TAB_CHAR"."COL" (actual: 4, maximum: 3)谢谢。
ありがとう。
Thank you for reading.

DIFFERENCE BETWEEN THE DATA DECLARATIONS NVARCHAR2 AND VARCHAR2(x CHAR)

CAN ANYONE HELP ME FIND THE DIFFERENCE BETWEEN THE DATA DECLARATIONS; NVARCHAR2 AND VARCHAR2(x CHAR), WHERE X IS THE SIZE OF DATA TO BE HELD WITH THE VARIABLE OR ATTRIBUTE

Duplicate posting....
Difference between nvarchar2(10) and varchar2(10 char )
Difference between nvarchar2( 10) and varchar2( 10 char)
Please refer also...
Nvarchar2

Difference between VARCHAR2(40 BYTE) and VARCHAR2(40 CHAR)

What is the difference between using VARCHAR2(40), VARCHAR2(40 BYTE0, and VARCHAR2(40 CHAR)

With a single byte character set the two definitions are effictively equal, but with a multibyte character set the two definitions will be different. Say you have built Oracle using a fixed 2 byte character set. 40 characters would be 80 bytes so the varchar2(40 BYTES) would hold only 20 characters.
Search on NLS parameters and database character set for more information.
HTH -- Mark D Powell --

Difference between Data Type Char & VarChar

Hi Experts,
I a design document that I have, some of the Data Types are mentioned as CHAR(e.g.CHAR(4)), and a few others as VARCHAR(e.g.VARCHAR(20)), can you let me know what is the difference between the two.And how is such an object to be developed in BW seeing that we don't have a DataType called Varchar in BW?
Thanks
Aravind

Hi
The char is a fixed-length character data type, the varchar is a variable-length character data type.
Because char is a fixed-length data type, the storage size of the char value is equal to the maximum size for this column. Because varchar is a variable-length data type, the storage size of the varchar value is the actual length of the data entered, not the maximum size for this column.
You can use char when the data entries in a column are expected to be the same size.
You can use varchar when the data entries in a column are expected to vary considerably in size.
but that is no need in SAP BW, any how you are going to assign the length of the variable while creating...
Thanks
M Kalpana

Differentiate between Char & number in Varchar2

Hey All,
I have Primary key in varchar2 and user entered Bank code sometime like CLR002, and some time BDRNN01, Now they want to make it auto number or Code, I tell them if they fix it from they beginning first 3 char for Code and last 3 for unique number then its easy for me to make it auto number or code.
Now I want know there is any Fuction avaliable that can differentiate between char & number in Varchar2 datatype?
Or any suggestion to solve this problem?
Thanks

e.g., your existing table is banking(bcode varcarch2(15),other_column...), then you back up it first as banking_bk, then add a new table banking(bankid number(6),bcode varcarch2(15),other_column...), then create a sequence number for it and FOR EACH ROW table trigger to auto-populate that column when INSERTING with that sequence number.
Then do inserting, then you get the old and new CODE mapping:
insert into banking(bcode varcarch2(15),other_column...)
select * from banking_bk;

Conversion/Type Cast of sys.XMLType to NUMBER and VARCHAR2

How do we typecast or convert a variable of the type sys.XMLType to NUMBER and VARCHAR2?
For e.g. I have a variable :-
v_STATE sys.XMLType
I want to convert it to either of the type NUMBER or VARCHAR2.

How do we typecast or convert a variable of the type sys.XMLType to NUMBER and VARCHAR2?
Your question is too vague to give a relevant answer.
Typecasting doesn't make sense in this situation, XMLType is an opaque datatype, it's not like converting VARCHAR2 to NUMBER (or vice versa).
Do you mean serializing the XML document, or extracting atomic node values, or something else ?
Depending on your requirement, you may want to look for XMLSerialize() or XMLCast() functions.
And on a side note, don't always expect people to search for your previous threads to find some useful information, such as a db version...

How to store pl/sql statement in varchar and call EXEC on it?

So this statement works:
SELECT column_name BULK COLLECT INTO table_column_list FROM all_tab_columns WHERE table_name = conv_tablename AND OWNER IN (SELECT USER FROM DUAL);
However I want to add conditions like " AND column_name <> 'abc' " at the end. So i tried to store this in a varchar and call EXEC on it:
select_column_value_sql_stmt := 'SELECT column_name BULK COLLECT INTO table_column_list FROM user_tab_columns WHERE table_name = '''|| conv_tablename || '''' || inexclude_column;
EXECUTE IMMEDIATE select_column_value_sql_stmt;
No matter how I concatenate the conv_tablename part, i get an error. either invalid identifier or unimplemented feature.
so is there a way to do this at all?
Thanks in advance.

Welcome to the forum!
Wheneve you post provide your 4 digit Oracle version (result of SELECT * FROM V$VERSION).
>
So this statement works:
SELECT column_name BULK COLLECT INTO table_column_list FROM all_tab_columns WHERE table_name = conv_tablename AND OWNER IN (SELECT USER FROM DUAL);
However I want to add conditions like " AND column_name 'abc' " at the end. So i tried to store this in a varchar and call EXEC on it:
select_column_value_sql_stmt := 'SELECT column_name BULK COLLECT INTO table_column_list FROM user_tab_columns WHERE table_name = '''|| conv_tablename || '''' || inexclude_column;
EXECUTE IMMEDIATE select_column_value_sql_stmt;
No matter how I concatenate the conv_tablename part, i get an error. either invalid identifier or unimplemented feature.
so is there a way to do this at all?
>
Yes - you can do it but the syntax is different for BULK COLLECT when using EXECUTE IMMEDIATE; the INTO goes AFTER the query, not within it.
See the example code at this link
http://unix-oracle-11g.blogspot.com/2011/03/dynamic-sql-execute-immediate-bulk.html
-- example of dynamic sql with bull collect
v_sql_stmt := 'SELECT sal FROM emp_t';
EXECUTE IMMEDIATE v_sql_stmt BULK COLLECT INTO vc_sal;So you won't be able to use a common set of queries for normal vs execute immediate.

Link between documentation for chars value and chars

Hi,
we need to find out sap transaction or report for link between documentation of chars value and chars.
we know for specific chars through CT04 and going to VALUES sub-tab then selecting perticular chars value and clicking on the documentation for value.

Go to transaction CT10 and select display option 'Allowed values'. You will have the characteristics along with their values.

The data types varchar and varchar are incompatible in the subtract operator

Hi ;
I want to fetch values 6,903,00 format ,my query is ;
SELECT CONVERT(varchar(50), CONVERT(money,SUM(DEBIT)),1) AS DEBIT ,CONVERT(varchar(50), CONVERT(money,SUM(CREDIT)),1),AS
CREDIT CONVERT(varchar(50), CONVERT(money,SUM(DEBIT)),1) - CONVERT(varchar(50), CONVERT(money,SUM(CREDIT)),1) AS BALANCE
FROM TABLE
it was get error : The data types varchar and varchar are incompatible in the subtract operator.
I want to Show result ;
DEBIT - CREDIT - BALANCE
6,903,00 4,387.24 2,515.76
Thanks in advance

You have to do the subtraction with the MONEY data type (prior to covert-ing).
Starting with SQL Server 2012, you can use the FORMAT command:
https://msdn.microsoft.com/en-us/library/hh213505.aspx
Kalman Toth Database & OLAP Architect
SQL Server 2014 Database Design
New Book / Kindle: Beginner Database Design & SQL Programming Using Microsoft SQL Server 2014
We have to use SQL 2005 due to licensing issue .

Performance between CLOB and VARCHAR2

I would like to know if there is any really performance issues between CLOB and VARCHAR2 data types?
In particular, why would it not be better to declare all large text items as CLOB rather than VARCHAR2(4000) in a table? For example, if I am going to store about a page of text, in a table, why not standardize of CLOB? Only use VARCHAR2 for small text items.

I doubt that there would be much, if any, performance difference between a CLOB and a VARCHAR2. By default, Oracle will store CLOBS directly in the table if they are less than about 4000 bytes, so the effect would be the same as a VARCHAR2(4000).
The advantage of VARCHAR2(4000) over a CLOB is that you document and enforce the maximum size of the field. If you know that no test item will exceed 4000 bytes, then I would store it as a VARCHAR2, because if they can store more, someone will.
A possible disadvantage of using CLOBS instead of VARCHAR2(4000) is that when you declare a column as a CLOB, Oracle creates the two lob segments whether or not they are needed to actually store data. So, depending on how many VARCHAR2(4000) columns you change to CLOBS without needing to store more than 4000 bytes, you can potentially waste a significant amount of space.
SQL> CREATE TABLE t_clob (id NUMBER, descr CLOB);
Table created.
SQL> SELECT segment_name, index_name
2 FROM dba_lobs
3 WHERE table_name = 'T_CLOB';
SEGMENT_NAME                   INDEX_NAME
SYS_LOB0000136329C00002$$      SYS_IL0000136329C00002$$
SQL> SELECT segment_name, segment_type, blocks
2 FROM dba_segments
3 WHERE segment_name in ('SYS_LOB0000136329C00002$$','SYS_IL0000136329C00002$$')
SEGMENT_NAME                   SEGMENT_TYPE           BLOCKS
SYS_IL0000136329C00002$$       LOBINDEX                   64
SYS_LOB0000136329C00002$$      LOBSEGMENT                 64HTH
John

Char, varchar and varchar2

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