Call stored procedure and register out parameter using JDBC Driver - jdbc

Question

We have written a stored procedure in Snowflake that inserts values in a table and returns a primary key. I'm trying to call this stored procedure using its JDBC driver.
final Connection connection = getJdbcTemplate().getDataSource().getConnection();
final CallableStatement callableStatement = connection.prepareCall("{call REWARD.sp_issue_reward(?, ?, ?)}");
callableStatement.setLong(1, reward.getClientSeq());
callableStatement.setLong(2, reward.getUserUniqueId());
callableStatement.registerOutParameter(3, Types.INTEGER); // throws SQLFeatureNotSupportedException
callableStatement.executeUpdate();
The connection.prepareCall returns an instance of SnowflakeCallableStatementV1.class. Problem is that this class has the following implementation for registering for output parameter:
/*
The Snowflake database does not accept OUT or INOUT parameters, so the registerOutParameter functions and the get
functions (which get values of OUT parameters) will remain not implemented)
*/
public void registerOutParameter(int parameterIndex, int sqlType) throws SQLException {
throw new SQLFeatureNotSupportedException();
}
A sample stored procedure definition that is in use:
create or replace procedure sp_issue_reward(CLIENT_SEQ float,
USER_SEQ float)
returns float not null
language javascript
called on null input
volatile
as
$$
var REWARD_ID = 1;
var insertStatement = snowflake.createStatement({
sqlText: "INSERT INTO REWARD.REWARD_CPY ("
+ "reward_seq, "
+ "client_seq, "
+ "user_seq) "
+ "VALUES (?, ?, ?)",
binds: [REWARD_ID, CLIENT_SEQ, USER_SEQ]
})
.execute();
return REWARD_ID;
$$;
How to get an output of a stored procedure using Snowflake JDBC driver?
Results are same with this stored procedure as well:
CREATE or replace PROCEDURE testSp()
RETURNS VARCHAR
LANGUAGE javascript
AS
$$
var rs = "Test"
return rs;
$$;

Answer 1

The problem is here:
callableStatement.executeUpdate();
When you're calling a stored procedure from JDBC, you're not executing an update. You're executing a query even though the SP is doing an update.
The stored procedure will return one row with a single column for the result. You can retrieve it like this:
Statement stmt = c.createStatement();
ResultSet rs = stmt.executeQuery("call TEST_JDBC()");
while (rs.next()) {
System.out.println(rs.getString(1));
}
You can of course get more sophisticated than this using prepared statements, but use executeQuery.