Analysis of the principle and implementation mechanism of MySQL timestamp

Analysis of the principle and implementation mechanism of MySQL timestamp

In the MySQL database, timestamp (Timestamp) is a data type used to store date and time information . It can record the number of seconds of the timestamp, accurate to the microsecond level, and is used to record information such as the creation time or last update time of data in the database. This article will analyze the principles and implementation mechanisms of MySQL timestamps and provide specific code examples.

1. The principle of MySQL timestamp

In MySQL, the timestamp is stored starting from the moment "1970-01-01 00:00:00" Number of seconds to record time. This is called a "Unix timestamp" and is a commonly used method of representing time. MySQL will automatically convert the timestamp internally, convert it to UTC time when storing, and then convert it to local time based on time zone and other information when querying.

It is worth noting that there are two types of timestamps in MySQL: TIMESTAMP and DATETIME. They differ slightly in how they are stored. TIMESTAMP will be affected by the time zone when storing, while DATETIME is not affected by the time zone, and the stored time is accurate to seconds.

2. MySQL timestamp implementation mechanism

MySQL uses system time to generate and store timestamps. When recording data, if the column type is defined as TIMESTAMP, MySQL will automatically assign the current timestamp to the column when a record is inserted. For the DATETIME type, you need to manually assign a timestamp to the column.

The following is a specific MySQL code example to illustrate the implementation mechanism of timestamp:

--Create a table containing columns of TIMESTAMP and DATETIME types
CREATE TABLE logs (
    log_id INT PRIMARY KEY,
    log_content VARCHAR(255),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP, -- TIMESTAMP type automatically assigns the current time
    modified_at DATETIME -- requires manual assignment
);

--Insert a record
INSERT INTO logs (log_id, log_content) VALUES (1, "Hello World");

-- Query the records
SELECT * FROM logs;

The above code creates a table named logs, including log_id, log_content, created_at and modified_at four columns, of which created_at is listed as TIMESTAMP type and modified_at is listed as DATETIME type . When inserting a record, the created_at column will be automatically assigned the current timestamp, while the modified_at needs to be assigned manually.

3. Summary

This article analyzes the principle and implementation mechanism of MySQL timestamp, and introduces the storage method of timestamp and its application in MySQL. By using columns of the TIMESTAMP and DATETIME types, you can easily record the time information of the data, and perform operations such as searching and comparing timestamps as needed. I hope this article will help you understand MySQL timestamps!

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