Shulou(Shulou.com)06/01 Report--

The following content mainly brings you the interpretation of the Mysql field type. the knowledge mentioned, which is slightly different from books, is summed up by professional and technical personnel in the process of contact with users, and has a certain value of experience sharing. I hope to bring help to the majority of readers.

Mysql is stored as files on the hard disk of our system, so

(1) there is a problem with disk IO when we read and write.

(2) when the data we store is stored in page units, and the size of each page is 16K, then we should store as much data per page as possible. The width of the table structure should not be too large, that is, the number of columns should not be too large, and the number of rows is more likely to be saved, so the problem of field type selection will be involved in storing the number of rows.

The following bytes are exemplified according to utf8. A Chinese occupies 3 bytes, a number and letter are one byte, and the utf8 is long, ranging from 1 to 6.

(1) numeric processing is faster than string processing.

(2) when we need to store a fixed length value (× ×, mobile phone number) and the length is less than 50 bytes, then we can choose char (n).

(3) choose varchar (n) when we want to store values greater than 50 bytes in length.

(4) when we store time, datatime > int > char > varchar, but int has a time limit and can only be saved until 2038.

(5) the choice of float and decimal, when we need to store a value with high precision, then we have to save decimal,float only to 7 places after the decimal point

The following is the number of bytes occupied by the type

For the interpretation of the above questions about Mysql field types, if you need to know more, you can continue to pay attention to the innovation of our industry. If you need professional answers, you can contact the pre-sales and after-sales on the official website. I hope this article can bring you some knowledge updates.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.