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I know that I can declare a varchar2 using the number of the characters that it should be able to contain.
However, in an Oracle database on which I am working, I found that a field (named PDF) is defined as follows:
VARCHAR2(1 BYTE) What does this mean? How many characters can it contain?
Another, related question: What is the difference between a VARCHAR and a VARCHAR2?
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Introduction to Oracle VARCHAR2 data type 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. By default, Oracle uses BYTE if you don't explicitly specify BYTE or CHAR after the max_size .
VARCHAR2(20 BYTE) : Allows only the specified number of bytes to be stored in the column, regardless of how many characters this represents. VARCHAR2(20 CHAR) : Allows the specified number of characters to be stored in the column regardless of the number of bytes this equates to.
Without specifying the maximum length for a VARCHAR2 parameter, the default is 4000 bytes.
You can declare columns/variables as varchar2(n CHAR) and varchar2(n byte).
n CHAR means the variable will hold n characters. In multi byte character sets you don't always know how many bytes you want to store, but you do want to garantee the storage of a certain amount of characters.
n bytes means simply the number of bytes you want to store.
varchar is deprecated. Do not use it. What is the difference between varchar and varchar2?
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