Realization of data synchronization between tables based on MySQL trigger

Trigger Simple to understand

Trigger (Trigger): Monitors a situation and triggers an action, which is a special stored procedure related to a table event, which is executed either by a program call or by a manual startup, but by an event, such as when working on a table (Insert,delete, Update) is activated when it is executed.
Triggers are often used to enforce data integrity constraints, business rules, and so on. Trigger creation syntax four elements:

1. 1. Watch location (table)
   2. Monitoring Events (Insert/update/delete)
   3. Trigger Time (After/before)
   4. Trigger Event (Insert/update/delete)

Demand:

Consistency of data between two tables in different databases

Ideas:

Based on the trigger when you operate on table 1, synchronize the operation to table 2

Steps:

Create a trigger that will do the same for table 2 when inserting, updating, and deleting data in table 1

Results:

Table data synchronization between different libraries within the same database connection is fully implemented

Triggers are transactional for two-table operations

Insert-time Trigger

DROP TRIGGER IF EXISTS ' insert_replication_application ';D elimiter;; CREATE TRIGGER INSERT  on  for Each ROW BEGIN INSERT  into VALUES (new value 1, new value 2); END ;;D Elimiter;

Update-time triggers

DROP TRIGGER IF EXISTS' update_replication_application ';D elimiter;;CREATE TRIGGER' Update_replication_application ' afterUPDATE  on' Source Library name '. ' Source table name ' forEach ROWBEGINUPDATE' Destination library name '. ' Destination table name 'SET' Destination Field 1 '=New. Modified value 1, ' Destination field 2 '=New. Modified Value 2,WHERE(' Destination primary key field '=Old . SOURCE primary key field);END;;D Elimiter;

Trigger when deleted

DROP TRIGGER IF EXISTS ' delete_replication_application ';D elimiter;; CREATE TRIGGER DELETE  on  for Each ROW BEGIN DELETE  from WHERE (' Destination primary key field '=old. SOURCE primary key field); END ;;D Elimiter;

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Realization of data synchronization between tables based on MySQL trigger