What type is used for mysql primary key?

Mysql primary key can use integer type, self-increasing integer type, UUID type or string type. Detailed introduction of types: 1. Integer type, one of the most common primary key types. In MySQL, different lengths can be used; 2. Self-increasing integer type, which can automatically assign a unique integer value as a primary key. This type is very suitable for use as Primary key, especially in scenarios that require high concurrent data insertion; 3. UUID type, a 128-bit globally unique identifier, which can ensure the global uniqueness of data; 4. String type, not recommended, etc.

The operating environment of this article: Windows 10 system, MySQL version 8.0.32, Dell g3 computer.

MySQL is a relational database management system that is widely used in the development of various web applications. In MySQL, the primary key is an important database concept used to uniquely identify each row of data in a table. The choice of primary key is very important. It not only ensures the integrity and consistency of the data, but also improves query efficiency. So, what type should be used for primary keys in MySQL?

There are multiple primary key types to choose from in MySQL, each type has its own characteristics and applicable scenarios. Depending on the specific situation, you can choose from the following common primary key types:

1. Integer type (INT): The integer type is one of the most common primary key types. In MySQL, the INT type can use different lengths, such as INT (11), INT (10), INT (5), etc. Generally speaking, INT(11) is the most common choice and can store integer values ​​from -2147483648 to 2147483647. If the amount of data is relatively large, you can choose the BIGINT type, which can store a larger range of integer values.

2. Self-increasing integer type (AUTO_INCREMENT): Self-increasing integer type is very commonly used in MySQL, it can automatically assign a unique integer value as the primary key. When creating a table, you can set the type of a column to INT (11) or BIGINT, and set it to the auto-increment attribute. Each time a new row is inserted, MySQL automatically generates a unique integer value for the column. Self-increasing integer types are ideal for use as primary keys, especially in scenarios where high concurrent data insertion is required.

3. UUID type (UNIVERSALLY UNIQUE IDENTIFIER): UUID is a 128-bit globally unique identifier. In MySQL, you can set the primary key type to UUID and use the UUID() function to generate a unique identifier. The UUID type can ensure the global uniqueness of data, but its disadvantage is that it takes up a lot of space.

4. String type (VARCHAR): The string type can be used as the primary key, but its use is not recommended. Using strings as primary keys may reduce query performance because comparisons of strings are slower than integer types. In addition, string type primary keys will also take up more storage space. If you must use a string as the primary key, you can set it to a shorter length to reduce the storage space occupied.

Summary

MySQL primary key can use integer type (INT or BIGINT), self-increasing integer type (AUTO_INCREMENT), UUID type or string type (VARCHAR). When selecting the primary key type, you need to make a reasonable choice based on the needs of the specific application and the characteristics of the data. For most cases, integer primary keys are the most common and reliable choice, providing high performance and scalability.

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