![]() Takes up 1 to 4 byte for each character based on collation and requires one or more bytes to store the length of the data Takes up 1 to 4 byte for each character, based on collation setting Use varying amounts of storage space based on the size of the string stored. Uses a fixed amount of storage, based on the size of the column Table 1: Differences between CHAR and VARCHAR To better understand the differences between these two data types, review the similarities and differences found in Table 1. The fundamental difference between CHAR and VARCHAR is that the CHAR data type is fixed in length, while the VARCHAR data type supports variable-length columns of data. Differences between CHAR and VARCHAR data types However, when you consider they only use the space they need, the savings in disk space alone might offset the performance cost of using a VARCHAR column. Because the length needs to be calculated and used by the database engine when reading and storing variable-length columns, they are considered a little less performant than CHAR columns. To support variable-length columns, the length of the data needs to be stored along with the data. For this reason, VARCHAR columns are great for storing strings that vary greatly in size. A variable-length column only takes up the space it needs to store a string of characters, with no spaces added to pad out the column. They can store characters, numbers, and special characters just like a CHAR column and can support strings up to 8000 bytes in size. VARCHAR columns, as the name implies, store variable-length data. VARCHAR the variable-length character data type ![]() Trailing spaces also make it a challenge when searching and using CHAR columns. ![]() Because CHAR columns are fully populated by adding spaces, when needed, each column uses the same amount of disk space or memory. ![]() The number of spaces padded is based on the size of the column less the length of characters being stored. When a CHAR column is populated with strings shorter than the length of the column, spaces will be padded to the right. This doesn’t mean a CHAR column can’t contain a value that varies in size. Columns storing things like addresses or memo fields would not be suitable for a CHAR column data type. A CHAR column would not be a good choice for storing data where the length varies greatly. For example, two-character State codes in the United States, single-character sex codes, phone numbers, postal codes, etc. CHAR data types are best used for storing data that is of a consistent length. It can store characters, numbers, and special characters in strings up to 8000 bytes in size. The CHAR data type is a fixed-length data type. CHAR the fixed-length character data type The information found in this article will help you decide when it is appropriate to use each of these data types. This article will discuss and compare these three different character data types. The CHAR, VARCHAR, and VARCHAR(MAX) data types can store character data. Will each value be the same length, or will the size vary greatly between values? How often will the data change? Will the length of the column change over time? There might also be other factors, like space efficiency and performance, that might drive your decision on a data type. When selecting a data type for a column, you need to think about the characteristics of the data to pick the correct data type. This article explains the differences between CHAR, VARCHAR, and VARCHAR(MAX). Picking the correct data type depends on the characteristics of the data being stored. Whether it is just stored in memory or on disk, each piece of data requires a data type. Some data is strictly numeric, while other data consists of only letters or a combination of letters, numbers, and even special symbols. In every database, there are different kinds of data that need to be stored. ![]()
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