What is difference between CHAR and VARCHAR2?What is the
maximum SIZE allowed for each type?
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Answer Posted / esakkiraja
CHAR
-----
SQL> CREATE TABLE char_test (col1 CHAR(10));
Table created.
SQL> INSERT INTO char_test VALUES ('qwerty');
1 row created.
SQL> SELECT col1, length(col1), dump(col1) "ASCII Dump"
FROM char_test;
COL1 LENGTH(COL1) ASCII Dump
---------- ------------ ------------------------------------
------------------------
qwerty 10 Typ=96 Len=10:
113,119,101,114,116,121,32,32,32,32
VARCHAR
-------
SQL> CREATE TABLE varchar_test (col1 VARCHAR2(10));
Table created.
SQL> INSERT INTO varchar_test VALUES ('qwerty');
1 row created.
SQL> SELECT col1, length(col1), dump(col1) "ASCII Dump"
FROM varchar_test;
COL1 LENGTH(COL1) ASCII Dump
---------- ------------ ------------------------------------
------------------------
qwerty 6 Typ=1 Len=6: 113,119,101,114,116,121
VARCAHR2
----------
SQL> CREATE TABLE varchar2_test (col1 VARCHAR2(10));
Table created.
SQL> INSERT INTO varchar2_test VALUES ('qwerty');
1 row created.
SQL> SELECT col1, length(col1), dump(col1) "ASCII Dump"
FROM varchar2_test;
COL1 LENGTH(COL1) ASCII Dump
---------- ------------ ------------------------------------
------------------------
qwerty 6 Typ=1 Len=6: 113,119,101,114,116,121
VARCHAR vs. VARCHAR2
---------------------
1. VARCHAR is going to be replaced by VARCHAR2 in next
version. So, Oracle suggests the use VARCHAR2 instead of
VARCHAR while declaring datatype.
2. VARCHAR can store up to 2000 bytes of characters while
VARCHAR2 can store up to 4000 bytes of characters.
3. If we declare datatype as VARCHAR then it will occupy
space for NULL values, In case of VARCHAR2 datatype it will
not occupy any space.
CHAR vs. VARCHAR
----------------
VARCHAR is used to store variable length character strings
up to 4000 characters. But, remember CHAR is faster than
VARCHAR - some times up to 50% faster.
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