You can also define your own parameters. These are especially useful for RDBMSs that don't allow user-defined variables.

User-defined parameters are defined (and set to null) when first referenced. They must start with ui and a period (ui.) if the parameter will only be referenced (input-only) and u and a period (u.) if the parameter will be updated (in/out). A user-defined parameter lasts for one synchronization—it is set to null at the start of every synchronization.

A typical use of user-defined parameters is to access state information without having to store it in a table (requiring potentially complex joins).

 Example

CREATE PROCEDURE MyCustomProc(
  IN username VARCHAR(128), INOUT var1 VARCHAR(128)
)
begin
 SET var1 = 'custom_value';
end

CALL ml_add_connection_script ( 
  'version1', 
  'begin_synchronization', 
  '{call MyCustomProc( {ml s.username}, {ml u.var1} )}' );

CALL ml_add_connection_script ( 
  'version1', 
  'select pk,col1 from MyTable where u_name = {ml s.username} and some_other_column = {ml ui.var1}' );

CALL ml_add_connection_script ( 
  'version1', 
  'prepare_for_download', 
  '{call MyPFDProc( {ml u.var1} )}' );

CALL ml_add_connection_script ( 
  'version1', 
  'begin_download', 
  'insert into SomeTable values( {ml s.username}, {ml ui.var1} )' );