Performance on datatype varcahr2(20) vs varchar2(200) - Ask TOM (2024)

FAQs

What is the difference between VARCHAR2 20 and VARCHAR2 20 char? ›

varchar2(20 char) means you can store 20 characters -- whereas varchar2(20) means you can store 20 bytes.

Note : There is no difference between VarChar and VarChar2 in Oracle. However, it is advised not to use VarChar for storing data as it is reserved for future use for storing some other type of variable.

CHAR is a fixed-length data type that pads values with spaces/fillers to meet the specified length. VARCHAR and VARCHAR2 are variable length data types that do not pad values. The length of a value in CHAR/VARCHAR is equal to the number of characters in it or bytes of space occupied by it.

The LONG datatype is like the VARCHAR2 datatype, except that the maximum size of a LONG value is 32760 bytes. You use the LONG RAW datatype to store binary data or byte strings. LONG RAW data is like LONG data, except that LONG RAW data is not interpreted by PL/SQL. The maximum size of a LONG RAW value is 32760 bytes.

Use varchar2 in instead of varchar if empty string and NULL are interchangeable. because it considers empty strings and null strings equally. Despite the fact that both are now used for the same purpose, Oracle advised, “Do not utilise varchar datatype.” However, future usage of varchar might alter.

For instance, a VARCHAR2(20 BYTE) column in an AL32UTF8 database could hold 20 characters from the ASCII range, 10 Latin letters with umlaut, 10 Cyryllic, 10 Hebrew, or 10 Arabic letters (2 bytes per character), or 6 Chinese, Japanese, Korean, or Devanagari (Indic) characters.

The difference between a CHAR and a VARCHAR is that a CHAR(n) will ALWAYS be N bytes long, it will be blank padded upon insert to ensure this. A varchar2(n) on the other hand will be 1 to N bytes long, it will NOT be blank padded. Using a CHAR on a varying width field can be a pain due to the search semantics of CHAR.

The maximum length for VARCHAR2 is 32672 BYTE or 8168 CHAR which is the same as the maximum length for VARCHAR of 32672 OCTETS or 8168 CODEUNITS32.

The short answer is: VARCHAR is variable length, while CHAR is fixed length. CHAR is a fixed length string data type, so any remaining space in the field is padded with blanks.

Use char when the sizes of the column data entries are consistent. Use varchar when the sizes of the column data entries vary considerably. Use varchar(max) when the sizes of the column data entries vary considerably, and the string length might exceed 8,000 bytes.

Is VARCHAR better than char? ›

One of the main advantages of using VARCHAR over CHAR is that it can save space in the database because it only uses the amount needed to store the actual data and not a fixed amount of space for all rows, regardless of the length of the stored string.

The VARCHAR2 data type specifies a variable-length character string in the database character set. You specify the database character set when you create your database. When you create a table with a VARCHAR2 column, you must specify the column length as size optionally followed by a length qualifier.

You must specify size for VARCHAR2 . Minimum size is 1 byte or 1 character. Maximum size is: 32767 bytes or characters if MAX_STRING_SIZE = EXTENDED.

The VARCHAR2 datatype takes a required parameter that specifies a maximum size up to 32767 bytes. We use the LONG datatype to store variable-length character strings. The LONG datatype is like the VARCHAR2 datatype, except that the maximum size of a LONG value is 32760 bytes.

The maximum size of the VARCHAR2 data type is 32,767 bytes. When you create a VARCHAR2 column, you must specify the maximum length for the VARCHAR2 column. Although the actual minimum string allowed for storage in a column of this type is a zero-length string (''), the maximum length must be at least 1 byte.

The difference between a CHAR and a VARCHAR is that a CHAR(n) will ALWAYS be N bytes long, it will be blank padded upon insert to ensure this. A varchar2(n) on the other hand will be 1 to N bytes long, it will NOT be blank padded. Using a CHAR on a varying width field can be a pain due to the search semantics of CHAR.

Char is best used when you expect the data values in a column to be the same length. On the other hand, varchar is best used when you expect the data values in a column to be of variable length.

The VARCHAR2 data type specifies a variable-length character string in the database character set. You specify the database character set when you create your database. When you create a table with a VARCHAR2 column, you must specify the column length as size optionally followed by a length qualifier.

So varchar2(10 char) is explicit. This can store up to 10 characters. Varchar2(10) is implicit. It may store 10 bytes or 10 characters, depending on the DB configuration.