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c067251840
Motivated by github PR #14. no-tn-check Change-Id: I866431c55fe0937f348d08cd8a188eb40fc8f061
84 lines
4.7 KiB
Ada
84 lines
4.7 KiB
Ada
------------------------------------------------------------------------------
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-- G N A T C O L L --
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-- --
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-- Copyright (C) 2005-2020, AdaCore --
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-- --
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-- This library is free software; you can redistribute it and/or modify it --
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-- under terms of the GNU General Public License as published by the Free --
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-- Software Foundation; either version 3, or (at your option) any later --
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-- version. This library is distributed in the hope that it will be useful, --
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHAN- --
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-- TABILITY or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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------------------------------------------------------------------------------
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-- This package provides additional subprograms to interact with a database
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-- in a tasking context.
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package GNATCOLL.SQL.Exec.Tasking is
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function Get_Task_Connection
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(Description : Database_Description;
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Username : String := "")
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return Database_Connection;
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-- Return the database connection specific to the current task. A new one
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-- is created if none existed yet, and the connection to the database is
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-- done automatically.
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-- If the thread is not connected yet, a new connection is created through
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-- Factory.
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-- The newly created connection and Username are then passed to
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-- Reset_Connection (see below).
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----------------------------------------------------------------------------
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-- The database independent cursor implementation. Could be used either --
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-- to provide Direct_Cursor for databases where it is not supported or --
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-- to provide data which could be shared between different tasks. --
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----------------------------------------------------------------------------
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function Task_Safe_Instance
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(Source : Forward_Cursor'Class;
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Index_By : Field_Index'Base := No_Field_Index) return Direct_Cursor;
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-- Creates and returns cursor which could be used to clone the copies for
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-- different tasks. This routine creates Source cursor data copy into
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-- internal structures of the resulting cursor. If the Source cursor
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-- already created using this routine, copy is not created but returned the
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-- Source cursor.
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-- Index_By could be supplied to index the result set by some field for
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-- the fast record lookup by the field value. Could be commonly used to
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-- lookup the record by the one field primary key.
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function Task_Safe_Instance
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(Source : Abstract_Cursor_Access;
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Index_By : Field_Index'Base := No_Field_Index)
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return Abstract_Cursor_Access;
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-- Need to support databases, where direct cursors is not supported.
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-- Returns the same pointer if the Source is already the task safe
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-- direct cursor.
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function Task_Safe_Clone (Source : Direct_Cursor) return Direct_Cursor;
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-- Clone the cursor copy to use in the current task and reset the copy to
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-- the first position,
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-- Source must be the result of a call to Task_Safe_Instance.
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-- The clone have to be made in the task where it will be used.
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-- Each task would use the same data, but own cursor pointer to the current
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-- record. If the Task_Safe_Clone called from the same task where the
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-- Task_Safe_Instance called, the routine returns the same Source cursor
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-- reset to the first position to avoid odd copy.
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procedure Find (Self : Abstract_Cursor_Access; Value : String);
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-- Search the record with specified field value over the internal cursor
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-- index by field defined on Prepare routine call in Index_By parameter.
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-- Set cursor position to the found row. If rows is not indexed, the
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-- Constraint_Error will be raised.
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end GNATCOLL.SQL.Exec.Tasking;
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