MySQL #1170 error (42000) blob/Text Column Used in key specification without a key length
Here is my solution to translating foreign websites.
When creating a new table or altering an existing table with primary key, unique constraints and
if the setting in an item is varchar (So, of course, the English isSo what about Chinese?Utf-8 in Chinese is 3 bytesSo, does this varchar (50) have only 16 characters to save? No, this is the case with MySQL, but not after 5.0.MySQL varchar (50)
You see this article from HTTP://WWW.CNBLOGS.COM/AYANMWReprinted from: http://blog.csdn.net/daydreamingboy/article/details/6310907Analyze the length of the MySQL data typeMySQL has several data types that can limit the "length" of a type, with char (
If a varchar is set in an item (50)
Well, that's 50 for English.
So what about Chinese?
Utf-8 Chinese occupies 3 bytes
So, is this varchar (50) Only save 16 characters?
MySQL varchar (50) in both Chinese and English, there are 50.
MySQL5
This article introduces the character length and related parameters of the varchar data type in mysql. For more information, see this article.
This article introduces the character length and related parameters of the varchar data type in mysql. For
What is the maximum length of int (11), and what is the maximum length of varchar in MySQL? What is the maximum length of int (11)?In the SQL statement, int represents the type of field you want to create, int represents an integer, and 11
MySQL study NOTE _ summary of MySQL character type VARCHAR length knowledge bitsCN.com
MySQL study NOTE _ summary of MySQL character type VARCHAR length
I. VARCHAR storage and row length restrictions
1. in VARCHAR (N), N refers to the length of
In MySQL, what is the maximum length of the varchar type? We will find that the varchar length is 65535 for the varchar data type, that is, 65532 bytes of data can be stored, is that true? Let's take a look.
1. Restrictions
Field restrictions
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
Next, I will provide a summary of mysql Data Types, that is, field types, including type descriptions and string lengths of different data types. I will introduce them below.
I. numeric type
Storage required for column typesTINYINT 1 byteSMALLINT 2
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