Delphi 7实现多线程操作内存表技术细节

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资源摘要信息:"Delphi 7 SQLMemTable_Thread多线程读写同一个内存表" 知识点详细说明: 1. Delphi 7环境下的多线程编程 Delphi 7是Embarcadero公司推出的一个集成开发环境(IDE),用于开发Windows应用程序。该版本内置了对多线程编程的支持,允许开发者创建和管理多个线程,实现并行处理和提高应用程序的性能。在这个案例中,使用Delphi 7实现多线程读写同一个内存表,展示了Delphi 7在多线程方面的应用。 2. SQLMemTable组件的使用 SQLMemTable是一个内存数据库表组件,允许开发者在应用程序中创建、存储、操作数据,而无需连接到外部的数据库服务器。它提供了一种快速且轻量级的数据存储解决方案,适合于需要高速访问和处理数据的场景。在这个案例中,使用SQLMemTable组件来实现内存中的表数据读写操作。 3. BMDThread控件的作用 BMDThread是第三方提供的一个线程控制组件,它提供了创建、管理线程的高级封装,简化了线程的创建和同步工作。它能够帮助开发者控制线程的启动、挂起、恢复和终止等操作,并处理线程间的通信问题。在这个案例中,BMDThread控件被用来协调多线程对内存表的访问,以确保数据的一致性和线程安全。 4. DBGridEh控件的使用 DBGridEh是用于显示和编辑表格数据的控件,通常与数据源组件配合使用。在这个案例中,DBGridEh控件可能被用于显示内存表SQLMemTable的数据,允许用户直观地查看和操作数据。通过这个控件,可以实现对内存表数据的增删改查操作。 5. 多线程读写同一个内存表的实现方法 在Delphi 7中,要实现多线程读写同一个内存表,首先需要创建多个线程。每个线程将负责不同的任务,比如一些线程可能被分配读取数据的任务,而其他线程可能被分配写入数据的任务。为了保证线程安全和数据一致性,需要在代码中加入必要的同步机制,如使用互斥锁(mutexes)、事件(events)、临界区(critical sections)等同步工具来避免竞态条件和死锁等问题。 6. 启动时读取数据SMemDB.db 在应用程序启动时,需要从指定的文件(如SMemDB.db)读取数据,并将其加载到内存表SQLMemTable中。这涉及到文件I/O操作和数据转换处理,确保应用程序可以正确地从持久化存储中读取数据到内存表中。 7. 退出时保存数据SMemDB.db 当应用程序关闭或用户触发保存操作时,需要将内存表SQLMemTable中的数据持久化保存回文件SMemDB.db。这一操作确保了内存表中的所有更改都能够被正确保存,防止数据丢失。 8. 循环操作中的线程读写 在循环操作中,可能会有两个线程进行数据写入,两个线程进行数据读取。这样的设计允许应用程序同时处理读写请求,提高应用程序的响应速度和处理能力。在实现时,开发者需要注意合理安排读写线程的优先级,以及合理地平衡读写负载。 总结: 通过Delphi 7的多线程功能,结合SQLMemTable内存表组件、BMDThread线程控制组件和DBGridEh数据显示组件,开发者可以创建一个可以同时处理多个读写请求的应用程序。通过合理的线程管理、同步机制和数据持久化处理,可以保证应用程序的稳定性和数据的一致性。该案例提供了在Delphi 7环境下处理复杂多线程数据操作的一套完整的实现方法。
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SQLMemTable for Delphi / C++ Builder: README============================================Please read this file carefully (especially the INSTALLATION chapter) before installing the program to your computer.Contents-------- Program information Company information Description Specification Features and Benefits Installation Purchasing / Registration Copyright and licenses Warranty and guarantee Technical support Important note Other products recommended to useProgram information-------------------Program Name: SQLMemTableLicense Types: Personal (for personal use, without source code) Com (for 1 developer, without source code) Pro (for 1 developer, with source code) Team4 (for 4 developers, with source code) Team8 (for 8 developers, with source code) Enterprise (Enterprise License - for entire company, with source code)Program Version: 1.00Program Release Date: 07/15/2003Program Purpose: SQLMemTable is a compact, fast and powerful in-memory table with SQL support. Target Environment: Delphi 4, 5, 6, 7 and C++ Builder 4, 5, 6.Company information-------------------Company Name: AidAim SoftwareContact E-mail Address: support@aidaim.comContact WWW URL: http://www.aidaim.comDescription-----------SQLMemTable is a compact in-memory table with SQL support for Delphi and C++ Builder. SQLMemTable does not require BDE and provides all the TTable‘s functionssuch as Master/Detail relationship, Filtering, Searching, Sorting, Key, Range, BLOB fields, and has some advanced features such as BLOB data compression, multi-indexes and table restructuring, shareable in memory capabilities. It is fully compatible with all standard DB controls, supports calculated and lookup fields as well as internationalization/localization and Unicode, provides data importing from and exporting to any dataset, includes SQLConsole utility with source code, comprehensive help and demos.SQLMemTable provides the following services: - SQL support - Master / detail relationship - Creating, renaming, emptying, deleting and restructuring tables - Creating, editing, deleting, navigating and searching for records - Creating and deleting multiple indexes - Calculated and lookup fields - Filtering support - Using BLOB fields with data compression ability - Importing from and exporting to any dataset in fast and easy way - Internationalization/Localization and Unicode supportSQLMemTable does not require BDE or any external drivers and has small footprint. Its search performance is excellent and data access speed is extremely fast.Specification-------------Data types: ftAutoInc, ftInteger, ftSmallInt, ftFloat, ftDateTime, ftDate, ftTime, ftBLOB, ftMemo, ftGraphic, ftString (any fixed length string), ftCurrency, ftWord, ftBoolean, ftLargeInt, ftFmtMemo, ftBytes, ftWideString.Advanced data types: aftExtended, aftWideMemoMaximum records quantity: up to 2^31 (over 2 billions). Maximum fields per table: 2^31 (over 2 billions). Maximum indexes per table: 2^31 (over 2 billions). Maximum index fields per index: 2^31 (over 2 billions). Maximum field name‘s length: 255 characters.Maximum index name‘s length: 255 characters.BLOB fields block size: > 1 byte, default 100 Kb. BLOB compression: ZLib, BZip, PPM Search operators: <,>,=,<>,<=,>=, like, not like, is null, is not null, and, or, not, (). Features and Benefits---------------------Compactness. - Short compiled code with approximate size 300 Kb, no external drivers (such as BDE) required. - Small memory consumption by SQLMemTable database engine. - Fast BLOB data compression. Your large data fields will need less memory. SQLMemTable can compress data on the fly. The compression routines used in the SQLMemTable are much faster than most of popular archivers like PKZip, WinRar, Arj. High performance. - Fast search by B-tree indexes. At the moment SQLMemTable is one of the fastest existing in-memory tables for Delphi and C++ Builder. - High-speed memory operations performance is achieved by means of using specially optimized memory manager and tuned algorithms. - Quick operations with strings. SQLMemTable compares strings up to 3 times faster than standard Delphi string routines. High performance is achieved by using a special library written in Assembler and an advanced sorting algorithm. - Advanced SQL optimizer often makes query execution several times faster by choosing the best execution plans. Functionality. - A subset of SQL‘92 including DDL operators is supported by TSQLMemQuery component. With SQLMemTable you can create SQL scripts for creating tables, inserting, editing and deleting records, retrieving data by SELECT command. - Advanced search engine. SQLMemTable supports ‘LIKE‘ operator with wildcards ‘%‘ and ‘_‘, as well as ‘IS NULL‘ and ‘IS NOT NULL‘ in filters and queries. - Full multiple index support, i.e. numerous fields in a table may comprise an index. SQLMemTable provides descending and ascending indexes, case-sensitive and insensitive indexes for string fields. - Shareable in-memory tables. SQLMemTable supports simultaneous access to a table by multiple TSQLMemTable components within a single application. - Default values support. - Record-level constraints, i.e. constraints that must be met when editing the data. Compatibility. - SQLMemTable supports most of TTable field data types, including BLOB fields, moreover it allows to create string and wide string fields of any fixed length. - SQLMemTable is fully compatible with standard DB-aware visual controls such as QuickReport, DBGrid, DBNavigator, DBImage, DBMemo, DBRichEdit, as well as with third party vendor‘s products supporting TDataset descendant components - FastReport, DBFlyTreeView and others. - Calculated and lookup fields can be used in the same way as TTable. - Most of TTable functions are supported including Key and Range methods. Convenience. - Table restructuring is being performed in the easiest way keeping all the existing data. - Data importing from and exporting to any dataset is supported. SQLMemTable provides you with the simplest way to import and export tables using ImportTable and ExportTable methods. - Internationalization / localization support. All text search and sorting functions use current system locale, so localizing your program with SQLMemTable is a very simple task. - Unicode support. All the text operations work with multi-byte encoding using ftWideString. - Comprehensive help. SQLMemTable comes with full documentation presented in SQLMemTable Developer‘s Guide and SQLMemTable Reference. Installation------------1) Make sure that all copies of Delphi (or C++ Builder) are currently closed and not running on the target system. Also, if you are replacing an existing version of SQLMemTable, please remove all files and the package of the prior version before running the new setup program.2) Unpack zip archive containing SQLMemTable into any directory. 3) Run the INSTALL.EXE from this directory.4) Follow on-screen instructions of step-by-step setup wizard to install SQLMemTable.5) If after the installation SQLMemTable components don‘t appear in Components Palette of the IDE, please follow the next instructions: * From the IDE, select ‘Component | Install Packages...‘. * Click the ‘Add‘ button. * In the ..SQLMemTableLibDelphi# (or ..SQLMemTableLibC++ Builder#) directory, select the dclSQLMemTableD#.BPL (or dclSQLMemTableB#.BPL) file. * Click the ‘OK‘ button to close the dialog. * Finally, select ‘Tools | Environment Options‘ from the main menu. From this dialog, select the ‘Library‘ tab and insure that the ..SQLMemTableLibDelphi# (or ..SQLMemTableLibC++ Builder#) directory is included in the ‘Library Path‘ line.Purchasing / Registration-------------------------Visit our site http://www.aidaim.com to purchase or register the product.Copyright and license---------------------See "license.txt" file.Warranty and guarantee----------------------See "license.txt" file.Technical support-----------------Before you contact us, please do the following: - Make sure you have performed all the required steps correctly. - Look at the Help files and Demos: it may already contain an answer to your question. A lot of people ask us something like "how do I:", though the complete information is there. - Visit our Internet site at http://www.aidaim.com. It‘s a good chance that you‘ll find the newer version of our product there.If the problem persists, please, inform us about the following: - SQLMemTable version. - Where did you obtain SQLMemTable (http or ftp site). - Compiler information: Delphi or C++ Builder, Version, Edition, Service Pack - Environmental information: your OS and Service Pack - Description of your problem (as much information as possible to retrieve the problem). - Attach a test project where the problem could be reproduced (it helps us to solve your issue as soon as possible)Typically AidAim Software Support Team answer messages in 24 hours, but depending on singularity and difficulty of your question it may take a bit longer.Should you have any ideas on improving the existing functions of this product after you have downloaded and used it, be easy to e-mail us. All registered users who buy this product may also send their offers to add new possibilities and/or to change the product‘s functions.We consider any ideas and we may take them into account while creating new versions of our products.Other products AidAim Software recommended-------------------------------------------All the products in this chapter are fully compatible with SQLMemTable and recommended to work with our product. AidAim Software had tested all these products released by our partner companies for complete compatibility with SQLMemTable. In its turn, all the partner companies have carried out similar testing of the compatibilityof SQLMemTable with their own products. All the companies whose products present here are technology partners of AidAim Software. It means that both partner companies guarantee the correct joint work of the products. In case of encountering bugs in the time of joint work and owing to it, the partners incur the obligation to resolve such problems for their clients for FREE. FastReport Software -------------------Advanced report generators for Delphi and Kylix.Web Site: http://www.fast-report.comFastReport VCL--------------FastReport VCL is reporting tool component for Borland Delphi 2-6 and Borland C++Builder 3-5. It consists of report engine, designer and preview. Some FastReport possibilities are really unique. The generator allows you to create tables, queries and databases in run-time. Built-in dialog designer allows you creation of dialog forms (they can be used for asking some parameters before printing a report). You also able to use built-in Pascal-like interpreter to do rather complex data processing. In spite of power of FastReport, its code is quite small. Probably FastReport is leader in correlation of functionality/size. The FastReport kernel (without designer) adds to your program the small footprint (less than QR3), but its functionality is like in ReportBuilder‘s one.FastReport CLX edition----------------------FastReport CLX edition is powerfull of FastReport for Borland Delphi 6 and Borland Kylix 1-2 for Linux. It use new CLX-library. Do you want to create reports for Linux as well as for Windows? Use FastReport CLX edition!FastReport VCL 2.3 lite-----------------------FreeWare version of FastReport. Imca Systems DevTeam --------------------Imca Systems DevTeam - Flexible and powerful Delphi/C++ Builder/ActiveX trees, grids and editors.Web Site: http://www.9rays.netDBFlyTreeView Suite-------------------Add grid and treeview functionality with a single component. DBFlyTreeView is a fully customizable, data-bound grid and tree view component that allows you to add huge arrays of nodes. OLE drag-and-drop is supported and the component is customizable at both design-time and runtime. DBFlyTreeView supports custom colors, fonts, and alignment for each cell, and you can even create scrollable background wallpapers without creating huge bitmaps.Included: RapidTree, FlyTreeView, PropertiesTree, DBFlyTreeView controls.DBFlyTreeViewPro Suite----------------------Enable your Delphi and C++Builder applications to display and browse hierarchical, table, and list data. DBFlyTreeViewPro Suite is a set of VCL components that are a direct descendent from FlyTreeViewPro. It supports more than 40 types of in place editors plus your custom format. It is data-aware and allows you to draw any array of cells directly to a printer, Metafile, or Bitmap canvas.Included: RapidTree, IsPlugeditor, FlyTreeViewPro, PropertiesTreePro, DBFlyTreeViewPro controls.