The data types to know are:

First, money serves as a medium of exchange, which means that money acts as an intermediary between the buyer and the seller. Second, money must serve as a store of value. In a barter system, we saw the example of the shoemaker trading shoes for accounting services.

(i) Money as medium of exchange solves the barter’s problem of lack of double coincidence of wants as money has separated the acts of sale and purchase. You can sell goods for money to whosoever wants it and with this money you can buy goods from whosoever wants to sell them.

• String (or str or text). Used for a combination of any characters that appear on a keyboard, such as letters, numbers and symbols.
• Character (or char). Used for single letters.
• Integer (or int). Used for whole numbers.
• Float (or Real).
• Boolean (or bool).

Numeric data types are normally used to store data like price, salary etc. Allows you to store a value 1, 0, or NULL . Stores integer values in the range from 0 to 255.

In this article

As the name suggests, varchar means character data that is varying. Also known as Variable Character, it is an indeterminate length string data type. It can hold numbers, letters and special characters.

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. For example, if you set a VARCHAR(100) data type = ‘Jen’, then it would take up 3 bytes (for J, E, and N) plus 2 bytes, or 5 bytes in all.

VARCHAR Datatype: It is a datatype in SQL which is used to store character string of variable length but maximum of set length specified. If the length of string is less than set or fixed length then it will store as it is without padded with extra blank spaces.

The effective maximum length of a VARCHAR is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used. VARCHAR(255) stores 255 characters, which may be more than 255 bytes.

variable character field

Varchar(50) stores a maximum of 50 characters. Varchar(max) stores a maximum of 2,147,483,647 characters. But, varchar(50) keeps the 50 character space even if you don’t store 50 characters. but varchar(max) is flexible to any size.

VARCHAR(256) is basically a 256-character variable length string – i.e. you can store a 3-character string in it, say lol , or a longer string, like this is a longer example of a string of text! , so long as it’s less than 256 characters in total.

The limit occurs due to an optimization technique where smaller strings are stored with the first byte holding the length of the string. Since a byte can only hold 256 different values, the maximum string length would be 255 since the first byte was reserved for storing the length.

varchar(100) means your variable FirstName can hold a value uuto hunder character, if the it is for 1000 it holds thousand characters. but unused characters do not consume storage. The storage will be n*1 byte+1= n1 bytes, in your case 100 = 100*1 byte +2 bytes=102 bytes.

Yes, is matter when you indexing multiple columns. Prefixes can be up to 1000 bytes long (767 bytes for InnoDB tables). In a latin1 collation, you can only specify up 3 columns of varchar(255) .