mysql varchar length performance

What is the meaning of the number after the int In the MySQL field? What is the significance of the number after varchar? mysql> create table t(a int(1));Query OK, 0 rows affected (0.10 sec)mysql> insert into t values(123);Query OK, 1 row affected (0.02 sec)mysql> insert int

I used to think that there are two bytes to record the length (a small length can also be recorded in one byte), so this problem was boring at the time, but someone in the group explained it later, it was suddenly discovered that it was not that simple.In mysql compact format, each record has a byte to indicate the distribution of NULL fields. If any field in the

Today, it is also a strange idea. MySQL verifies that varchar (15) will save 15 Chinese characters, and the first 15 will be automatically intercepted if the number exceeds 15. This concept may come from SQL server. In the varchar type, Chinese occupies two bytes. Therefore, only half of the varchar

Text and varchar character indexes are invalid when innodb in mysql is a uft8 character set. The index length of a single field is limited to 767 bytes due to the index length limit in the innodb utf8 character set. The maximum index length is: The InnoDB internal maximum ke

I was asked a question: what is the maximum varchar length in MySQL? This is not a fixed number. This article briefly describes the restrictions.1. Restrictions on Rule fields The following rules apply when defining a field: a) the storage restriction varchar field stores the actual content separately in the clustered

A question was asked: What is the maximum length of varchar in MySQL?This is not a fixed number. This article briefly describes the restrictions.1. When defining a field, the following rules apply to the field restriction: www.2cto.com a) Storage restriction varchar field stores the actual content separately in the clu

exceed 65535. b Coding Length Limit If the character type is GBK, each character is up to 2 bytes and the maximum length cannot exceed 32766; If the character type is UTF8, each character is up to 3 bytes, and the maximum length cannot exceed 21845. For a more English forum, use GBK to occupy 2 bytes per character, while using UTF-8 English is only one byte.

The varchar type of MySQL database tutorial has a maximum length limit of 255 in the version below 5.0.3, and its data range can be 0~255. In the MySQL5.0.3 and above versions, the length of the varchar data type is supported to 65535, which means that 65,532 bytes of data

The length of the varchar field of mysql is found to be insufficient in terms of varchar when designing system fields. I have set a field. the type is VARCHER, And I tested it. it is found that not much is full. I think it is strange that MYSQL 5.5 or above does not have a

converted to the text type and produces warning. c) The length of the limit The length of a row definition is the limit of the varchar length in the actual application. MySQL requires a row to have a defined length of not more

An interesting question: the maximum length of varchar in MySQLThe minimum heap of 1 K is obviously maintained, but only nine hundred rows of data are output to MySQL. Check the log and find the following content: 01stderr logs02com.mysql.jdbc.MysqlDataTruncation: Data truncation: Data too long for column 'reqs' at row 103 at com.mysql.jdbc.MysqlIO.checkErrorP

during definition, the varchar field is forcibly converted to the text type and generates a warning. C) row length limitIn practice, the length of a varchar is limited by the length defined by a row. MySQL requires that the defin

In the version above MySQL5.0, the length of the varchar data type is supported to 65535, which means that 65,532 bytes of data can be stored, and the start and end bits take up 3 bytes, that is, data stored in a fixed text or blob format in 4.1 or below can be used with variable length varchar to store, this will effe

What is the maximum varchar length in MySQL? This is not a fixed number. 1. Restrictions Field restrictions include the following rules when a field is defined: A) Storage restrictions The varchar field stores the actual content separately in the clustered index. The content starts with 1 to 2 bytes to indicate t

length exceeds 255 ), therefore, the maximum length cannot exceed 65535. B)Encoding length limit If the character type is GBK, each character occupies a maximum of 2 bytes, and the maximum length cannot exceed 32766; If the character type is utf8, each character occupies up to 3 bytes, and the maximum