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This article is mainly about "what is the use of mysql's replace into sentence". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "what's the use of mysql's replace into sentence"?

Replace into and insert into are very similar, the only difference is that when using replace into, it will first judge whether there is the same record as the statement that will be replace into according to the primary key of the table, and if so, delete the old record first, and then insert the new record. And replace into will return a value after execution. A value of 1 means that a piece of data is inserted during execution, and a value of 2 means that the old record is deleted and the new record is inserted during execution. Although there are no serious problems in the normal use of replace into. If there is a self-increasing primary key in the table we are working on, there will be a problem. First, because the primary key value of the new record is different from that of the old record, all associations established with the old data primary key id of this table in other tables will be destroyed. Second, frequent REPLACE INTO results in a rapid increase in the value of the primary key for new records. One day. After reaching the maximum value, it will overflow because the data is too large. You won't be able to insert a new record. The data table is full, not because there is not enough space, but because the value of the primary key cannot be increased any more.

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