SharpFileDB - a file database for small apps
SharpFileDB - a file database for small apps
本文中文版在此处。
I'm not an expert of database. Please feel free to corect my mistakes.
This article (http://www.cnblogs.com/gaochundong/archive/2013/04/24/csharp_file_database.html) helpes a lot. Thank you!
目标(Goal)
I've decided to write a micro database library that spports 10 thousand level applications.
It's better not to rely on other drives or tools in case of high difficulty in deployment. After all, it's a small database for a small application.
It's a DLL from totally C# codes. It's easy for reading and using.
It supports CRUD of course.
It doesn't use any SQL. I'm not familiar with SQL and I don't like it. And it's not necessary to use SQL here.
It saves data via plain text files or binary files. It's convenient to use plain text files when developing and debugging codes. And it's safer to use binary files at deployment time.
So, simply, it's a micro database library that uses no SQL, files as storage form and totally C# to implement a CRUD system. Let's name the library SharpFileDB.
I've put the newest project on Github. All codes in the library are noted in both chinese and engilsh. I hope that will help to communicate.
设计草图(sketch)
使用场景(User Scene)
The typical user scene of SharpFileDB is as follows.
// common cases to use SharpFileDB.
FileDBContext db = new FileDBContext(); Cat cat = new Cat();
cat.Name = "xiao xiao bai";
db.Create(cat); Predicate<Cat> pre = new Predicate<Cat>(x => x.Name == "xiao xiao bai");
IList<Cat> cats = db.Retrieve(pre); cat.Name = "xiao bai";
db.Update(cat); db.Delete(cat);
This routine contains lines that create a database and uses CRUD operations.
Let's start the first version of SharpFileDB according to this user scene.
表vs类型(Table vs Type)
Let's take the type 'Cat' as an example.
/// <summary>
/// demo file object
/// </summary>
public class Cat : FileObject
{
public string Name { get; set; }
public int Legs { get; set; } public override string ToString()
{
return string.Format("{0}, Name: {1}, Legs: {2}", base.ToString(), Name, Legs);
}
}
The type 'Cat' is equivalent to a 'Table' in a relational database.
An instance of 'Cat' is equivalent to a record of a 'Table'.
Lets' call types like 'Cat' a table-type.
全局唯一的主键(global unique main key)
We need a global unique main key for every instance of a table-type to diffentiate them. So let's do this in an abstract class.
/// <summary>
/// 可在文件数据库中使用CRUD操作的所有类型的基类。
/// Base class for all classed that can use CRUD in SharpFileDB.
/// </summary>
[Serializable]
public abstract class FileObject
{
/// <summary>
/// 主键.
/// main key.
/// </summary>
public Guid Id { get; set; } /// <summary>
/// 创建一个文件对象,并自动为其生成一个全局唯一的Id。
/// <para>Create a <see cref="FileObject"/> and generate a global unique id for it.</para>
/// </summary>
public FileObject()
{
this.Id = Guid.NewGuid();
} public override string ToString()
{
return string.Format("Id: {0}", this.Id);
}
}
数据库(FileDBContext)
All table-types' CRUD operations are done in a FileDBContext.
/// <summary>
/// 文件数据库。
/// Represents a file database.
/// </summary>
public class FileDBContext
{
#region Fields /// <summary>
/// 文件数据库操作锁
/// <para>database operation lock.</para>
/// </summary>
protected static readonly object operationLock = new object(); /// <summary>
/// 文件数据库
/// <para>Represents a file database.</para>
/// </summary>
/// <param name="directory">数据库文件所在目录<para>Directory for all files of database.</para></param>
public FileDBContext(string directory = null)
{
if (directory == null)
{
this.Directory = Environment.CurrentDirectory;
}
else
{
Directory = directory;
}
} #endregion public override string ToString()
{
return string.Format("@: {0}", Directory);
} #region Properties /// <summary>
/// 数据库文件所在目录
/// <para>Directory of database files.</para>
/// </summary>
public virtual string Directory { get; protected set; } #endregion protected string Serialize(FileObject item)
{
using (StringWriterWithEncoding sw = new StringWriterWithEncoding(Encoding.UTF8))
{
XmlSerializer serializer = new XmlSerializer(item.GetType());
serializer.Serialize(sw, item);
string serializedString = sw.ToString(); return serializedString;
}
} /// <summary>
/// 将字符串反序列化成文档对象
/// </summary>
/// <typeparam name="TDocument">文档类型</typeparam>
/// <param name="serializedFileObject">字符串</param>
/// <returns>
/// 文档对象
/// </returns>
protected TFileObject Deserialize<TFileObject>(string serializedFileObject)
where TFileObject : FileObject
{
if (string.IsNullOrEmpty(serializedFileObject))
throw new ArgumentNullException("data"); using (StringReader sr = new StringReader(serializedFileObject))
{
XmlSerializer serializer = new XmlSerializer(typeof(TFileObject));
object deserializedObj = serializer.Deserialize(sr);
TFileObject fileObject = deserializedObj as TFileObject;
return fileObject;
}
} protected string GenerateFileFullPath(FileObject item)
{
string path = GenerateFilePath(item.GetType());
string name = item.GenerateFileName();
string fullname = Path.Combine(path, name);
return fullname;
} /// <summary>
/// 生成文件路径
/// </summary>
/// <typeparam name="TDocument">文档类型</typeparam>
/// <returns>文件路径</returns>
protected string GenerateFilePath(Type type)
{
string path = Path.Combine(this.Directory, type.Name);
return path;
} #region CRUD /// <summary>
/// 增加一个<see cref="FileObject"/>到数据库。这实际上创建了一个文件。
/// <para>Create a new <see cref="FileObject"/> into database. This operation will create a new file.</para>
/// </summary>
/// <param name="item"></param>
public virtual void Create(FileObject item)
{
string fileName = GenerateFileFullPath(item);
string output = Serialize(item); lock (operationLock)
{
System.IO.FileInfo info = new System.IO.FileInfo(fileName);
System.IO.Directory.CreateDirectory(info.Directory.FullName);
System.IO.File.WriteAllText(fileName, output);
}
} /// <summary>
/// 检索符合给定条件的所有<paramref name="TFileObject"/>。
/// <para>Retrives all <paramref name="TFileObject"/> that satisfies the specified condition.</para>
/// </summary>
/// <typeparam name="TFileObject"></typeparam>
/// <param name="predicate">检索出的对象应满足的条件。<para>THe condition that should be satisfied by retrived object.</para></param>
/// <returns></returns>
public virtual IList<TFileObject> Retrieve<TFileObject>(Predicate<TFileObject> predicate)
where TFileObject : FileObject
{
IList<TFileObject> result = new List<TFileObject>();
if (predicate != null)
{
string path = GenerateFilePath(typeof(TFileObject));
string[] files = System.IO.Directory.GetFiles(path, "*.xml", SearchOption.AllDirectories);
foreach (var item in files)
{
string fileContent = File.ReadAllText(item);
TFileObject deserializedFileObject = Deserialize<TFileObject>(fileContent);
if (predicate(deserializedFileObject))
{
result.Add(deserializedFileObject);
}
}
} return result;
} /// <summary>
/// 更新给定的对象。
/// <para>Update specified <paramref name="FileObject"/>.</para>
/// </summary>
/// <param name="item">要被更新的对象。<para>The object to be updated.</para></param>
public virtual void Update(FileObject item)
{
string fileName = GenerateFileFullPath(item);
string output = Serialize(item); lock (operationLock)
{
System.IO.FileInfo info = new System.IO.FileInfo(fileName);
System.IO.Directory.CreateDirectory(info.Directory.FullName);
System.IO.File.WriteAllText(fileName, output);
}
} /// <summary>
/// 删除指定的对象。
/// <para>Delete specified <paramref name="FileObject"/>.</para>
/// </summary>
/// <param name="item">要被删除的对象。<para>The object to be deleted.</para></param>
public virtual void Delete(FileObject item)
{
if (item == null)
{
throw new ArgumentNullException(item.ToString());
} string filename = GenerateFileFullPath(item);
if (File.Exists(filename))
{
lock (operationLock)
{
File.Delete(filename);
}
}
} #endregion CRUD }
FileDBContext
文件存储方式(Way to store files)
SharpFileDB creates a directory for every table-types in the database's folder. Every instance of a table-type are stored in its respective directory as a single XML file. The file's name is same with the instance's Id.
下载(Download)
I've put the project on github(https://github.com/bitzhuwei/SharpFileDB/) and you are welcom to try, create issues and fork it.
PS: I think this small file database library can help some people. It's where we are that needs us.
SharpFileDB - a file database for small apps的更多相关文章
- 小型文件数据库 (a file database for small apps) SharpFileDB
小型文件数据库 (a file database for small apps) SharpFileDB For english version of this article, please cli ...
- BIT祝威博客汇总(Blog Index)
+BIT祝威+悄悄在此留下版了个权的信息说: 关于硬件(Hardware) <穿越计算机的迷雾>笔记 继电器是如何成为CPU的(1) 继电器是如何成为CPU的(2) 关于操作系统(Oper ...
- EBS R12 修改 apps 密码[Z]
注意:修改密码时应保证所有用户已退出, 最好是关闭应用实例.不用关闭数据库.在修改密码之前一定要改备下数据库中的FND_ORACLE_USERID和FND_USER表.FNDCPASS工具会自动把AP ...
- File System Programming --- (二)
File System Basics The file systems in OS X and iOS handle the persistent storage of data files, app ...
- swat主流域文件(file.cio)参数详解——引自http://blog.sciencenet.cn/blog-922140-710636.html
% file.clo,即主流域文件用于文件管理,包括与模型选项.气候输入.数据库和输出控制相关的信息. Master Watershed File: file.cio Project Descript ...
- Database(Mysql)发版控制二
author:skate time:2014/08/18 Database(Mysql)发版控制 The Liquibase Tool related Database 一.Installation ...
- Inno Setup connection to the database and create
原文 Inno Setup connection to the database and create Description: the first half of this program in I ...
- DISQLite3 - A self-contained, embeddable, zero-configuration SQL database engine for Delphi
DISQLite3 implements a self-contained, embeddable, zero-configuration SQL database engine for Delphi ...
- How to get the MD5 checksum for a file: md5sum, digest, csum, fciv
LINUX: md5sum fileName In Linux, the md5sum utility can be used: aemtux1:/ % md5sum binary.file 0c46 ...
随机推荐
- [翻译]Telnet简单介绍及在windows 7中开启Telnet客户端
文章翻译自 http://social.technet.microsoft.com/wiki/contents/articles/910.windows-7-enabling-telnet-clien ...
- EXT.NET 使用总结(3)--动态图表
动态生成雷达图--Radar 效果图: aspx页面代码: <ext:Panel ID="ResultPanel" Border="true" runat ...
- NXP恩智浦P87C51/52/54/58/591芯片解密单片机破解多少钱?
NXP恩智浦P87C51/52/54/58/591芯片解密单片机破解 芯片解密型号: P87C51x2.P87C52x2.P87C54x2.P87C58x2.P87C591 单片机解密 #####[ ...
- 11大Java开源中文分词器的使用方法和分词效果对比
本文的目标有两个: 1.学会使用11大Java开源中文分词器 2.对比分析11大Java开源中文分词器的分词效果 本文给出了11大Java开源中文分词的使用方法以及分词结果对比代码,至于效果哪个好,那 ...
- 浩瀚科技 定制现场无线手持打印PDA手持终端扫描条码开单解决方案
PDA通过扫描商品条码移动开单,实现便携式办公,伴随式销售,是深圳市浩瀚技术有限公司的一款最新安卓微POS产品,PDA能通过WIFI无线局域网.GPRS互联网直接与主机电脑连接,让公司业务人员能随时随 ...
- ipad上自定义view的旋转适配
ios8横屏时宽高会自动转换,但是ios7不是 CGFloat screenWidth = [UIScreen mainScreen].bounds.size.width; CGFloat scree ...
- iOS图片拉伸技巧
纵观移动市场,一款移动app,要想长期在移动市场立足,最起码要包含以下几个要素:实用的功能.极强的用户体验.华丽简洁的外观.华丽外观的背后,少不了美工的辛苦设计,但如果开发人员不懂得怎么合理展示这些设 ...
- 查看java源码显示source not found
除了下载的jar包之外,还要下载src源码的zip包. 进项目的Java Build Path里找到你想看源码的jar包 Source Attachment Configuration--Extern ...
- Gridview中几个Button的应用
gridview中有三种方式添加button的应用,CommandField.ButtonField.TemplateField中加Button这三种方式.三种方式都可以实现同样的功能,但在实现某些功 ...
- brew管理node的版本
摘要 nvm可以.brew怎么去切换不同的node版本 转载请注明出处:http://my.oschina.net/uniquejava/blog/491030 brew详解:http://stack ...