mysql insert unique

Key differs from primary keyKey is usually the index synonym. If the keyword attribute primary key is given in the column definition, then primary key can also be specified as key only. The purpose of this is to be compatible with other database

One, background Before using SQL Server for table partitioning, there were a lot of questions about unique indexes: Step8:sql Server When table partitions encounter a unique constraint, I did not think that in the MySQL partition will encounter the

When mysql processes a unique index, it updates the index. If it does not exist, it should be very common to insert the index. There are many similar articles on the Internet, today I will talk about the problems and methods that may occur when this

When a unique column inserts a record containing duplicate values on a unique key, we can control how MySQL handles this: Skip inserts using the Ignore keyword or on the DUPLICATE key update clause, Break operations or update old records for new

This article will introduce the differences between unique and primary constraints in mysql. unique and primary are the types we often use when creating mysql. Next I will introduce them to you. Fields defining the UNIQUE constraint cannot contain

When inserting records with duplicate values on a unique key, we can control how MySQL handles this situation: using the IGNORE keyword or on DUPLICATE key UPDATE clause skips the INSERT, interrupts the operation, or updates the old record to the

This article is a MySQL database insert, UPDATE, delete and replace statements in the use of detailed analysis of the introduction, the need for friends to refer to the MySQL database insert and UPDATE statements Introduction: The SQL used to

This article mainly introduces in inserting the data to the table to encounter the key duplication avoids inserting the duplicate value the processing method, mainly relates to Ignore,on DUPLICATE key update,replace; then look at the three ways to

If mysql processes an index, it is updated. If there is no index, it is inserted (multiple columns of unique indexes). If there is no index, It is very common to insert the index, there are many similar articles on the Internet. Today I will talk

How does mysql insert a field to a table? this field will randomly generate a unique code. how does mysql insert a field to a table? this field will randomly generate a unique code ------ solution ------------------ if php is used you can use uniqid