Boolean function
AdaBase.Driver.Base.[DB].trait_multiquery_enabled ()

This is a connection attribute. It returns True if the driver is configured to accept multiple queries separated by semicolons in the query string. This feature is fully supported by all drivers, but it only applies to direct statements. Prepare statements are limited to single queries by definition. This attribute is False by default on all drivers.


Procedure
AdaBase.Driver.Base.[DB].set_trait_multiquery_enabled (trait : Boolean)

This procedure is used to set the multiquery support. It can be set anytime (before or after establishing the connection).

The SQLite driver supports multiple queries in direct statements by default, and in fact this behavior cannot be disabled. Attempting to do so results in an exception (demonstrated below). 

with AdaBase;
with Connect;
with Ada.Text_IO;
with Ada.Exceptions;

procedure MultiQuery is

   package CON renames Connect;
   package TIO renames Ada.Text_IO;
   package EX  renames Ada.Exceptions;

   numrows : AdaBase.Affected_Rows;
   setting : Boolean;
   nextone : Boolean;

   SQL : constant String :=
         "DELETE FROM fruits WHERE color = 'red'; " &
         "DELETE FROM fruits WHERE color = 'orange'";
begin

   CON.connect_database;

   TIO.Put_Line ("This demonstration shows how multiple queries in the " &
                 "same SQL string are handled.");
   TIO.Put_Line ("SQL string used: " & SQL);
   TIO.Put_Line ("");

   setting := CON.DR.trait_multiquery_enabled;
   nextone := not setting;

   TIO.Put_Line ("Testing query with MultiQuery option set to " & setting'Img);
   TIO.Put_Line ("--  Execution attempt #1  --");
   begin
      numrows := CON.DR.execute (SQL);
      TIO.Put_Line ("Query succeeded");
      CON.DR.rollback;
   exception
      when ouch : others =>
         TIO.Put_Line ("Exception: " & EX.Exception_Message (ouch));
         TIO.Put_Line ("Failed to test this setting");
   end;

   TIO.Put_Line ("");
   TIO.Put_Line ("Attempt to toggle MultiQuery setting to " & nextone'Img);
   begin
      CON.DR.set_trait_multiquery_enabled (nextone);
      TIO.Put_Line ("--  Execution attempt #2  --");
      numrows := CON.DR.execute (SQL);
      TIO.Put_Line ("Query succeeded");
      CON.DR.rollback;
   exception
      when ouch : others =>
         TIO.Put_Line ("Exception: " & EX.Exception_Message (ouch));
         TIO.Put_Line ("Failed to test this setting");
   end;

   CON.DR.disconnect;

end MultiQuery;

testcases/multiquery/multiquery.adb


This demonstration shows how multiple queries in the same SQL string are handled.
SQL string used: DELETE FROM fruits WHERE color = 'red'; DELETE FROM fruits WHERE color = 'orange'

Testing query with MultiQuery option set to FALSE
--  Execution attempt #1  --
Exception: Driver is configured to allow only one query at time, but this SQL contains multiple queries: DELETE FROM fruits WHERE color = 'red'; DELETE FROM fruits WHERE color = 'orange'
Failed to test this setting

Attempt to toggle MultiQuery setting to TRUE
--  Execution attempt #2  --
Query succeeded

Output using any driver


[DB] is "MySQL.MySQL_Driver", "PostgreSQL.PostgreSQL_Driver", or "SQLite.SQLite_Driver"

See Also