Introduction to the Use method of update nowait in Oracle _oracle

1, UPDATE nowait Apply the following scenario: Query a data and open database transactions to it. If the current data for the query is not locked, the result is returned correctly and the current data is locked, if the current data for the query is already locked in the transaction. But return exception information: Prompt data has been locked. SQL statement:

SQL code :

Copy Code code as follows:

SELECT *
From Hold_mc_site_product_pic pic
WHERE pic.id = 730127 for UPDATE nowait

2, the application in the case of multithreading concurrency. First query the data to be processed, and add database-level locks, after processing, write to the database. Commit the transaction. Can effectively control the concurrency of data consistency.