zoukankan      html  css  js  c++  java
  • Using INSERT IGNORE with MySQL to prevent duplicate key errors

    An error will occur when inserting a new record in MySQL if the primary key specified in the insert query already exists. Using the "IGNORE" keyword prevents errors from occuring and other queries are still able to be run.

    Why?

    Although you shouldn't normally attempt to insert a record without first checking if the primary key you want to use has already been used, there may be times when this is required, such as when multiple developers need to update their own copies of a database, and a particular record may already exist in one or other of the databases.

    Inserting a single record

    The syntax is simple - just add "IGNORE" after "INSERT" like so:

    INSERT IGNORE INTO mytable
        (primaryKey, field1, field2)
    VALUES
        ('abc', 1, 2);

    Inserting multiple records

    When inserting mutiple records at once, any that cannot be inserting will not be, but any that can will be:

    INSERT IGNORE INTO mytable
        (primaryKey, field1, field2)
    VALUES
        ('abc', 1, 2),
        ('def', 3, 4),
        ('ghi', 5, 6);

    In the second example above, if records already existed for 'abc' and 'def' then those two records would not be inserted, but the record for 'ghi' would be.

    https://www.electrictoolbox.com/mysql-insert-ignore/

  • 相关阅读:
    mysql 主从复制原理
    java操作ldap
    ldap数据库--ldapsearch,ldapmodify
    ldap数据库--ODSEE--ACI
    ldap数据库--ODSEE--schema
    ldap数据库--ODSEE--复制协议
    ldap数据库--ODSEE--suffix
    ldap数据库--ODSEE--卸载
    ldap数据库--ODSEE--安装
    WebService--cxf
  • 原文地址:https://www.cnblogs.com/softidea/p/6855036.html
Copyright © 2011-2022 走看看