mysql varchar length performance

Php judges that the input does not exceed the length range of the mysql varchar field. However, if the input is UTF-8 encoded, a Chinese character occupies three characters, for example, string $ str = "Hello !! "; If you use the strlen function to judge that the length is 11, which is more than the

This article mainly describes how to use PHP to determine the input does not exceed the length of the MySQL field of the varchar range, has a certain reference value, now share to everyone, the need for friends can refer to varchar Type field, if you set the length to 10,

Php judges that the input does not exceed the length range of the mysql varchar field. However, in UTF-8 encoding, a Chinese character occupies three characters, for example, the string $ str "Hello !!"; If you use the strlen function to determine that the length is 11, which is more than the value of varch. However, i

However, if the Utf-8 encoding, a Chinese character is 3 characters in length, such as the string $str= "Hello Ah!!"; If you use the Strlen function to judge that the length is 11, just over the length of the varchar, but in fact it is not so, if directly into the phpMyAdmin inside the INSERT statement, this string c

Tags: http using data ar SP on EF Database sqlMany tutorials say varchar (here with varchar (5) example, UTF-8 encoding) the data stored in the database is not long, such as you save "AB" and "in", one occupies 2 bytes, one occupies 3 bytes, because in the disk storage when the number of bytes is different, so you need to record the length.Is the MySQL char still

Label:If the setting in an item is varchar (50) Then of course the English is 50 then the Chinese is utf-8 3 bytes So, is this varchar (50) only able to save 16 characters? No, this is the case with MySQL, but not after 5.0.MySQL varchar (50) Both Chinese and English are sto

It has always been thought that there are two bytes to record the length (a small length can also be recorded in a byte), so the problem was very boring at that time, but then some people in the group to explain, suddenly found that the original thing is not so simple The MYSQL compact format, each record has a byte to represent the null field distribution, if t

Although this should not happen, usually like our relational database, we should be designed in advance, can not be changed later, but because of the negligence of the work before, in fact, it is not only my personal negligence, the main reason for communication, of course, the database is my design, so, or self-criticism. About the situation: MySQL field has a varchar value field set too short, set 30, (I

The limit for total index length is: The InnoDB internal maximum key length is 3500 bytes, but MySQL itself restricts this to 3072. (1024 bytes for non-64-bit builds before MySQL 5.0.17, and for all builds before 5.0.15.) In the UTF8 character set, the [data portion] of varchar