next:jdbc How to allow multiple statements for SQL Server - sql

Question

I want to run multiple statements on a single execution against SQL Server. I do it with Node.js but I cannot run the same query using next.jdbc
For example, if I run this:
(def db {:jdbcUrl "jdbc:jtds:sqlserver://localhost:1433/TESTDB;user=sa;password=passwd"})
(def ds (jdbc/get-datasource db))
(jdbc/execute! ds ["select * from EMPLOYEE;select FIRST_NAME from EMPLOYEE;"])
I have also tried to wrap the statement within a transaction with the same result
(jdbc/execute! ds ["BEGIN TRANSACTION select * from EMPLOYEE;select FIRST_NAME from EMPLOYEE; COMMIT"])
I always get the first query.
I have tried Microsoft's JDBC driver also.
Sean Corfield says that if the database supports it, then next.jdbc should support it. next-jdbc: execute multiple statements?
But I cannot make it work
Solution
As indicated by Sean Corfield
(jdbc/execute! ds ["BEGIN select * from EMPLOYEE;select FIRST_NAME from EMPLOYEE; END"] {:multi-rs true})

Answer 1

Yes, you can run multiple statements and multiple result sets back but you have to tell next.jdbc that's the behavior you want.
Take a look at the tests for MS SQL Server running multiple statements: https://github.com/seancorfield/next-jdbc/blob/develop/test/next/jdbc_test.clj#L560-L572
This is mentioned (briefly) in the Getting Started guide: "If you pass the :multi-rs true option to execute!, you will get back a vector of results sets, instead of just one result set: a vector of zero or more vectors."

Answer 2

As far as I know, SQL Server's JDBC driver does not support multiple statements. But, even if it did, you should probably not be using it, as it opens a potential security hole for injection type attacks. Instead, if you really need to execute multiple SQL statements, either refactor your current SQL into a single statement, or else use multiple statements wrapped in a single transaction.
For reference, some other JDBC drivers, such as MySQL, might support multiple statements.