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Version: v11.7.1

Concurrency and Record Locking in WaveMaker


Use Case

How to handle the scenario wherein two users update a row in a Database Table at the same time.

The document explains the implementation for obtaining concurrency and record locking in WaveMaker.We will be using MariaDB on MySQL Cloud setup.

Steps

  1. Create a MariaDB database. See the following the documentation link for details
  2. Add a table with the following columns:
    • ID - type integer,
    • Name - type String name, and
    • Version - type long.
  3. Go to the File Explorer and navigate to the following directory:
<project_name>/services/<database_name>/src/com/<project_name>/<database_name>/<table_name>
  • Add @Version annotation for the version column as shown below.

  • Add the below import statement.
import javax.persistence.Version;
note

Please note the @Version annotation added in the above step might get reverted each time a DB re-import operation is performed, hence replace the @Version after each DB re-import.

  1. Create a Page in the app.
  2. Drag and drop a Data Table widget into the page and set the data source as the table/entity designed in Step #2.
  3. Open the Advanced Settings of the Data Table widget and uncheck the Show property for the version column.

  1. Run the application and insert/update values into the Data Table widget. When two users update a row in the data table at the same time, only one of the transactions will be completed whereas the other call will fail with an error message.