在C#中运用 SQLite

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在C#中运用 SQLite 作者:IcyCoffee  来源:blog.csdn.net/icycoffee  时间:2010-3-8  【 字体:大 中 小 】 〖 双击滚屏 〗   

  SQLite 是一个嵌入式的联系数据库系统,运用十分广泛。在一些数据量不大的运用 程序中,假如运用 SQLite可以极大的降低部署时的工作量。 要在C#中运用 SQLite也很基本,只要找一个C#的wrapper就可以了,例如,我运用的就是来自
  http://sqlite.phxsoftware.com/  的一个dll,System.Data.SQLite. 下载下来的文件是SQLite-1.0.65.0-setup.exe。只要安装一下就可以运用了,特别方便。该程序契合 ADO.NET的规范,并且支撑 Visual Studio的可视化表设计器。
  打开Visual Studio 2008,新建一个Console Application,为此项目添加System.Data.SQLite的引用。添加一个数据库连接,此时可以发觉,新建连接中有了一个SQLite Database Connection,挑选此类型的数据连接,并且新建一个文件,
  test.db3. 接下来在新数据库中添加一张表。

  下面开始为此表建立一个Data Access类,以展示在C#中如何 运用 SQLite,可以想象,和操作其他数据库是几乎一样的,感谢ADO.NET的功劳。
  最先是一个实体类 Book.cs:
public class Book
    {
        private int id;
        private string bookName;
        private decimal price; 
        public int ID
        {
            get { return id; }
            set { id = value; }
        }
        public string BookName
        {
            get { return bookName; }
            set { bookName = value; }
        }
        public decimal Price
        {
            get { return price; }
            set { price = value; }
        }
    } 

 


  编写DAL类: 
using System;
using System.Collections.Generic;
using System.Text;
using System.Data.SQLite; 
namespace ConsoleApplication1
{
    public class BookDAL
    {
        public static bool Create(Book book)
        {
            try
            {
                using (SQLiteConnection conn = new SQLiteConnection("Data Source=e://test.db3"))
                {
                    conn.Open();
                    SQLiteCommand cmd = conn.CreateCommand();
                    cmd.CommandText = "insert into Book
(id,bookname,price) 

 values(@ID,@BookName,@Price);";
                    cmd.Parameters.Add(new SQLiteParameter("ID", book.ID));
                    cmd.Parameters.Add(new SQLiteParameter("BookName", book.BookName));
                    cmd.Parameters.Add(new SQLiteParameter("Price", book.Price));
                    int i = cmd.ExecuteNonQuery();
                    return i == 1;
                }
            }
            catch (Exception)
            {
                //Do any logging operation here if necessary
                return false;
            }
        } 
        public static bool Update(Book book)
        {
            try
            {
                using (SQLiteConnection conn = new SQLiteConnection("Data Source=e://test.db3"))
                {
                    conn.Open();
                    SQLiteCommand cmd = conn.CreateCommand();
                    cmd.CommandText = "update Book set BookName=@BookName,Price=@Price where ID=@ID;";
                    cmd.Parameters.Add(new SQLiteParameter("ID", book.ID));
                    cmd.Parameters.Add(new SQLiteParameter("BookName", book.BookName));
                    cmd.Parameters.Add(new SQLiteParameter("Price", book.Price));
                    int i = cmd.ExecuteNonQuery();
                    return i == 1;
                }
            }
            catch (Exception)
            {
                //Do any logging operation here if necessary
                return false;
            }
        } 
        public static bool Delete(int ID)
        {
            try
            {
                using (SQLiteConnection conn = new SQLiteConnection("Data Source=e://test.db3"))
                {
                    conn.Open();
                    SQLiteCommand cmd = conn.CreateCommand();
                    cmd.CommandText = "delete from Book where ID=@ID;";
                    cmd.Parameters.Add(new SQLiteParameter("ID", ID));         
                    int i = cmd.ExecuteNonQuery();
                    return i == 1;
                }
            }
            catch (Exception)
            {
                //Do any logging operation here if necessary
                return false;
            }
        } 
        public static Book GetbyID(int ID)
        {
            try
            {
                using (SQLiteConnection conn = new SQLiteConnection("Data Source=e://test.db3"))
                {
                    conn.Open();
                    SQLiteCommand cmd = conn.CreateCommand();
                    cmd.CommandText = "select * from Book where ID=@ID;";
                    cmd.Parameters.Add(new SQLiteParameter("ID", ID));
                    SQLiteDataReader dr = cmd.ExecuteReader();
                    if (dr.Read())
                    {
                        Book book = new Book();
                        book.ID = dr.GetInt32(0);
                        book.BookName = dr.GetString(1);
                        book.Price = dr.GetDecimal(2);
                        return book;
                    }
                    else
                        return null;
                }
            }
            catch (Exception)
            {
                //Do any logging operation here if necessary
                return null;
            }
        }
    }
} 
 
  编写测试主程序: 
using System; 
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Book book = new Book();
            book.ID = 1;
            book.BookName = "Book A";
            book.Price = 10.0m;
            BookDAL.Create(book); 
            book.ID = 2;
            book.BookName = "第二本书";
            book.Price = 13.0m;
            BookDAL.Create(book); 
            book = BookDAL.GetbyID(2);
            Console.WriteLine(book.ID + " " + book.BookName + " " + book.Price); 
            book.Price = 11.1m;
            BookDAL.Update(book); 
            book = BookDAL.GetbyID(2);
            Console.WriteLine(book.ID + " " + book.BookName + " " + book.Price);
            book = BookDAL.GetbyID(1);
            Console.WriteLine(book.ID + " " + book.BookName + " " + book.Price); 
        }
    }
} 

  结尾 结果:
2 第二本书 13
2 第二本书 11.1
1 Book A 10

//---------------------------------------------------------------

using System.Data;
using System.Data.Common;
using System.Data.SQLite;

// 创建数据库文件
File.Delete("test1.db3");
SQLiteConnection.CreateFile("test1.db3");

DbProviderFactory factory = SQLiteFactory.Instance;
using (DbConnection conn = factory.CreateConnection())
{
  // 连接数据库
  conn.ConnectionString = "Data Source=test1.db3";
  conn.Open();

  // 创建数据表
  string sql = "create table [test1] ([id] INTEGER PRIMARY KEY, [s] TEXT COLLATE NOCASE)";
  DbCommand cmd = conn.CreateCommand();
  cmd.Connection = conn;
  cmd.CommandText = sql;
  cmd.ExecuteNonQuery();

  // 添加参数
  cmd.Parameters.Add(cmd.CreateParameter());
  
  // 开始计时
  Stopwatch watch = new Stopwatch();
  watch.Start();
  
  // 连续插入1000条记录
  for (int i = 0; i < 1000; i++)
  {
    cmd.CommandText = "insert into [test1] ([s]) values (?)";
    cmd.Parameters[0].Value = i.ToString();

    cmd.ExecuteNonQuery();
  }

  // 停止计时
  watch.Stop();
  Console.WriteLine(watch.Elapsed);
}

哎~~~~ 一个常识性的错误,我加几行代码 (新增代码标记 "// <-------------------")。
using System.Data;
using System.Data.Common;
using System.Data.SQLite;

// 创建数据库文件
File.Delete("test1.db3");
SQLiteConnection.CreateFile("test1.db3");

DbProviderFactory factory = SQLiteFactory.Instance;
using (DbConnection conn = factory.CreateConnection())
{
  // 连接数据库
  conn.ConnectionString = "Data Source=test1.db3";
  conn.Open();

  // 创建数据表
  string sql = "create table [test1] ([id] INTEGER PRIMARY KEY, [s] TEXT COLLATE NOCASE)";
  DbCommand cmd = conn.CreateCommand();
  cmd.Connection = conn;
  cmd.CommandText = sql;
  cmd.ExecuteNonQuery();

  // 添加参数
  cmd.Parameters.Add(cmd.CreateParameter());
  
  // 开始计时
  Stopwatch watch = new Stopwatch();
  watch.Start();
  
  DbTransaction trans = conn.BeginTransaction(); // <-------------------
  try 
  {
    // 连续插入1000条记录
    for (int i = 0; i < 1000; i++)
    {
      cmd.CommandText = "insert into [test1] ([s]) values (?)";
      cmd.Parameters[0].Value = i.ToString();

      cmd.ExecuteNonQuery();
    }

    trans.Commit(); // <-------------------
  }
  catch
  {
    trans.Rollback(); // <-------------------
    throw; // <-------------------
  }

  // 停止计时
  watch.Stop();
  Console.WriteLine(watch.Elapsed);
}

执行一下,耗时 0.2 秒。