[ https://issues.apache.org/jira/browse/CASSANDRA-18465?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jacek Lewandowski reassigned CASSANDRA-18465: --------------------------------------------- Assignee: Jacek Lewandowski > Add support for multiple condition branches and results in Accord transaction > ----------------------------------------------------------------------------- > > Key: CASSANDRA-18465 > URL: https://issues.apache.org/jira/browse/CASSANDRA-18465 > Project: Cassandra > Issue Type: New Feature > Components: Accord, CQL/Syntax > Reporter: Jacek Lewandowski > Assignee: Jacek Lewandowski > Priority: Normal > > I'd like to propose adding support for multiple branches and result sets for > Accord transactions. It could look like this: > {code:sql} > BEGIN TRANSACTION > LET a = ... > LET b = ... > IF condition THEN > SELECT 'one', a.value > UPDATE ... > ELSE IF condition2 THEN > SELECT 'two', b.value > UPDATE ... > ELSE > SELECT 'three', NULL > END IF > COMMIT TRANSACTION > {code} > The existing syntax would remain valid, when a single SELECT is defined in > which case the conditional SELECTs would not be valid. > SELECTs would be validated to return columns of the same type. They would be > able to return literals as well. > This would be make the result of the transaction more intuitive as the client > would know explicitly if the updates where applied or not. > The following syntax would be considered as invalid: > 1. select defined both on the top level and in branches > {code:sql} > BEGIN TRANSACTION > LET a = ... > LET b = ... > SELECT ... > IF condition THEN > SELECT 'one', a.value > UPDATE ... > ELSE IF condition2 THEN > SELECT 'two', b.value > UPDATE ... > ELSE > SELECT 'three', NULL > END IF > COMMIT TRANSACTION > {code} > 2. select defined after update - select must be before the update to make it > clear we select data before modification > {code:sql} > BEGIN TRANSACTION > LET a = ... > LET b = ... > IF condition THEN > UPDATE ... > SELECT 'one', a.value > ELSE IF condition2 THEN > UPDATE ... > SELECT 'two', b.value > ELSE > SELECT 'three', NULL > END IF > COMMIT TRANSACTION > {code} > 3. missing select - if select is defined in a single branch, it has to be > defined in all branches: > {code:sql} > BEGIN TRANSACTION > LET a = ... > LET b = ... > IF condition THEN > SELECT 'one', a.value > UPDATE ... > ELSE IF condition2 THEN > SELECT 'two', b.value > UPDATE ... > ELSE > UPDATE ... > END IF > COMMIT TRANSACTION > {code} > {code:sql} > BEGIN TRANSACTION > LET a = ... > LET b = ... > IF condition THEN > SELECT 'one', a.value > UPDATE ... > END IF > COMMIT TRANSACTION > {code} -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@cassandra.apache.org For additional commands, e-mail: commits-h...@cassandra.apache.org