What is VARCHAR and VARCHAR2 in SQL?
Varchar stands for variable length character string. Both Varchar and Varchar2 are data types to store character strings for particular column (field) in databases. … If we relay empty string and NULL being the same, then we should use varchar2 instead of varchar. Because it treats both null and empty strings as same.
What is the difference between CHAR and VARCHAR2 datatype in SQL?
Difference between CHAR and VARCHAR datatypes
2. In CHAR, If the length of string is less than set or fixed length then it is padded with extra memory space. In VARCHAR, If the length of string is less than set or fixed length then it will store as it is without padded with extra memory spaces.
What is VARCHAR2 data type in SQL?
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.
What is VARCHAR2 example?
A VARCHAR2 column can store a value that ranges from 1 to 4000 bytes. It means that for a single-byte character set, you can store up to 4000 characters in a VARCHAR2 column. … For example, if you define a VARCHAR2 column with a maximum size is 20. In a single-byte character set, you can store up to 20 characters.
Should I use VARCHAR or VARCHAR2?
VARCHAR is reserved by Oracle to support distinction between NULL and empty string in future, as ANSI standard prescribes. VARCHAR2 does not distinguish between a NULL and empty string, and never will. If you rely on empty string and NULL being the same thing, you should use VARCHAR2 .
Why VARCHAR is used in SQL?
As the name suggests, varchar means character data that is varying. … SQL varchar usually holds 1 byte per character and 2 more bytes for the length information. It is recommended to use varchar as the data type when columns have variable length and the actual data is way less than the given capacity.
Why is it called VARCHAR2?
VARCHAR is an ANSI Standard that is used to distinguish between Null and Empty Strings. However, in Oracle VARCHAR and VARCHAR2 is totally the same.
Difference between char, varchar and VARCHAR2 in Oracle.
|2||It is used to store character string of fixed length||It is used to store character string of variable length|
What does VARCHAR 20 mean?
The data type of varchar is Variable-length with non-Unicode character data. The storage size is the actual length of data entered + 2 bytes. • For varchar (20): The max storage size is: 20*1 byte +2 bytes=22 bytes; •
Is CHAR and VARCHAR same?
CHAR is fixed length and VARCHAR is variable length. CHAR always uses the same amount of storage space per entry, while VARCHAR only uses the amount necessary to store the actual text. The char is a fixed-length character data type, the varchar is a variable-length character data type.
What is raw data type?
In Oracle PL/SQL, RAW is a data type used to store binary data, or data which is byte oriented (for example, graphics or audio files). One of the most important things to note about RAW data is that it can only be queried or inserted; RAW data cannot be manipulated.
What is primary key SQL?
In SQL, a primary key is a single field or combination of fields that uniquely defines a record. None of the fields that are part of the primary key can contain a NULL value. A table can have only one primary key. You use either the CREATE TABLE statement or the ALTER TABLE statement to create a primary key in SQL.
Is VARCHAR a string?
VARCHAR is a variable length string data type, so it holds only the characters you assign to it. VARCHAR takes up 1 byte per character, + 2 bytes to hold length information.
How is VARCHAR2 defined?
The VARCHAR2 datatype stores variable-length character strings. When you create a table with a VARCHAR2 column, you specify a maximum column length (in bytes, not characters) between 1 and 2000 for the VARCHAR2 column.
How do you put more than 4000 characters into CLOB?
- split the long character string into 4000 character or less chunks.
- create clobs for each chunk using to_clob() function.
- concatenate the clobs.
What is VARCHAR2 10?
VARCHAR2(10 char) could support as much as 40 bytes of information and will support to up 10 characters of data. Varchar2(10) uses the current value of NLS_LENGTH_SEMANTICS to determine the limit for the string. incase of byte, then it’s 10 bytes. incase of char, then it’s 10 characters.