How to synchronize database access in Spring

[hignattarge]

I encounter a problem on accessing and updating data on mySQL in Spring framework, and I want to ask everyone the most efficient way to lock a TABLE row.Let's say I have two tables: one records all circles with their ids and positions, the other records all squares with the same columns. each circle's position can be modified independently, so do the squares. But squares' positions can also be adjusted by moving the position of the circles. pseudo-code as following:\[code\]Public ShapeMovingService{ @Transaction (isolation=required) public moveCirclePosition(int id, int newPosition){ //move circle=id to a new position //also move the square which relates to this circle accordingly } @Transaction (isolation=required) public moveSquarePosition(int id, int newPosition){ //move square=id to a new position } }public CircleDao extends JdbcTemplateSupport{ public updatePosition(int id, int position){ //query a circle from circle TABLE with id //update the position of the circle //ALSO: modify the position of the square which relates to this circle }} public SquareDao extends JdbcTemplateSupport{ public updatePosition(int id, int position){ //query a square from squareTABLE with id //update the position of the square }} \[/code\]I made several threads to do the following tasks:

• Two threads keep updating the position of the circle id=1
• One thread keeps updating the position of the circle id=2
• One thread keeps updating the position of the square id=1
• One thread keeps updating the position of the square id=2

Moving the position of the circle id=2 will affect the position square id=1; circle id=1 has no relation to other squares, neither does square id=2.My question is, at which point should I lock the database operation, either by transaction annotation or synchronized keyword, so that no data corruption will occur? Yet different circles can still be updated simultaneously. Right now I lock the updatePosition function, but that means only one circle/square can be updated at a time. Thank you for any suggestions.