C#操作SQLite增删改模板<转载>

iojsioi

using System;

using System.Data;

using System.Data.Common;

using System.Data.SQLite;

namespace SQLiteQueryBrowser

{

    /// <summary>

    /// 说明：这是一个针对System.Data.SQLite的数据库常规操作封装的通用类。

    /// 作者：zhoufoxcn(周公）

    /// 日期：2010-04-01

    /// Blog:http://zhoufoxcn.blog.iyunv.com or http://blog.csdn.net/zhoufoxcn

    /// Version:0.1

    /// </summary>

    public class SQLiteDBHelper

    {

        private string connectionString = string.Empty;

        /// <summary>

        /// 构造函数

        /// </summary>

        /// <param name="dbPath">SQLite数据库文件路径</param>

        public SQLiteDBHelper(string dbPath)

        {

            this.connectionString = "Data Source=" + dbPath;

        }

        /// <summary>

        /// 创建SQLite数据库文件

        /// </summary>

        /// <param name="dbPath">要创建的SQLite数据库文件路径</param>

        public static void CreateDB(string dbPath)

        {

            using (SQLiteConnection connection = new SQLiteConnection("Data Source=" + dbPath))

            {

                connection.Open();

                using (SQLiteCommand command = new SQLiteCommand(connection))

                {

                    command.CommandText = "CREATE TABLE Demo(id integer NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE)";

                    command.ExecuteNonQuery();

                    command.CommandText = "DROP TABLE Demo";

                    command.ExecuteNonQuery();

                }

            }

        }

        /// <summary>

        /// 对SQLite数据库执行增删改操作，返回受影响的行数。

        /// </summary>

        /// <param name="sql">要执行的增删改的SQL语句</param>

        /// <param name="parameters">执行增删改语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param>

        /// <returns></returns>

        public int ExecuteNonQuery(string sql, SQLiteParameter[] parameters)

        {

            int affectedRows = 0;

            using (SQLiteConnection connection = new SQLiteConnection(connectionString))

            {

                connection.Open();

                using (DbTransaction transaction = connection.BeginTransaction())

                {

                    using (SQLiteCommand command = new SQLiteCommand(connection))

                    {

                        command.CommandText = sql;

                        if (parameters != null)

                        {

                            command.Parameters.AddRange(parameters);

                        }

                        affectedRows = command.ExecuteNonQuery();

                    }

                    transaction.Commit();

                }

            }

            return affectedRows;

        }

        /// <summary>

        /// 执行一个查询语句，返回一个关联的SQLiteDataReader实例

        /// </summary>

        /// <param name="sql">要执行的查询语句</param>

        /// <param name="parameters">执行SQL查询语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param>

        /// <returns></returns>

        public SQLiteDataReader ExecuteReader(string sql, SQLiteParameter[] parameters)

        {

            SQLiteConnection connection = new SQLiteConnection(connectionString);

            SQLiteCommand command = new SQLiteCommand(sql, connection);

            if (parameters != null)

            {

                command.Parameters.AddRange(parameters);

            }

            connection.Open();

            return command.ExecuteReader(CommandBehavior.CloseConnection);

        }

        /// <summary>

        /// 执行一个查询语句，返回一个包含查询结果的DataTable

        /// </summary>

        /// <param name="sql">要执行的查询语句</param>

        /// <param name="parameters">执行SQL查询语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param>

        /// <returns></returns>

        public DataTable ExecuteDataTable(string sql, SQLiteParameter[] parameters)

        {

            using (SQLiteConnection connection = new SQLiteConnection(connectionString))

            {

                using (SQLiteCommand command = new SQLiteCommand(sql, connection))

                {

                    if (parameters != null)

                    {

                        command.Parameters.AddRange(parameters);

                    }

                    SQLiteDataAdapter adapter = new SQLiteDataAdapter(command);

                    DataTable data = new DataTable();

                    adapter.Fill(data);

                    return data;

                }

            }

 

        }

        /// <summary>

        /// 执行一个查询语句，返回查询结果的第一行第一列

        /// </summary>

        /// <param name="sql">要执行的查询语句</param>

        /// <param name="parameters">执行SQL查询语句所需要的参数，参数必须以它们在SQL语句中的顺序为准</param>

        /// <returns></returns>

        public Object ExecuteScalar(string sql, SQLiteParameter[] parameters)

        {

            using (SQLiteConnection connection = new SQLiteConnection(connectionString))

            {

                using (SQLiteCommand command = new SQLiteCommand(sql, connection))

                {

                    if (parameters != null)

                    {

                        command.Parameters.AddRange(parameters);

                    }

                    SQLiteDataAdapter adapter = new SQLiteDataAdapter(command);

                    DataTable data = new DataTable();

                    adapter.Fill(data);

                    return data;

                }

            }

        }

        /// <summary>

        /// 查询数据库中的所有数据类型信息

        /// </summary>

        /// <returns></returns>

        public DataTable GetSchema()

        {

            using (SQLiteConnection connection = new SQLiteConnection(connectionString))

            {

                connection.Open();

                DataTable data = connection.GetSchema("TABLES");

                connection.Close();

                //foreach (DataColumn column in data.Columns)

                //{

                //        Console.WriteLine(column.ColumnName);

                //}

                return data;

            }

        }

    }

}

 

完整的程序例子：

using System;

using System.Collections.Generic;

using System.Text;

using System.Data;

using System.Data.Common;

using System.Data.SQLite;

using SQLiteQueryBrowser;

namespace SQLiteDemo

{

    class Program

    {

        static void Main(string[] args)

        {

            //CreateTable();

            //InsertData();

            ShowData();

            Console.ReadLine();

        }

        public static void CreateTable()

        {

            string dbPath = "D:\\Demo.db3";

            //如果不存在改数据库文件，则创建该数据库文件

            if (!System.IO.File.Exists(dbPath))

            {

                SQLiteDBHelper.CreateDB("D:\\Demo.db3");

            }

            SQLiteDBHelper db = new SQLiteDBHelper("D:\\Demo.db3");

            string sql = "CREATE TABLE Test3(id integer NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,Name char(3),TypeName varchar(50),addDate datetime,UpdateTime Date,Time time,Comments blob)";

            db.ExecuteNonQuery(sql, null);

        }

        public static void InsertData()

        {

            string sql = "INSERT INTO Test3(Name,TypeName,addDate,UpdateTime,Time,Comments)values(@Name,@TypeName,@addDate,@UpdateTime,@Time,@Comments)";

            SQLiteDBHelper db = new SQLiteDBHelper("D:\\Demo.db3");

            for (char c = "A"; c <= "Z"; c++)

            {

                for (int i = 0; i < 100; i++)

                {

                    SQLiteParameter[] parameters = new SQLiteParameter[]{

                                                 new SQLiteParameter("@Name",c+i.ToString()),

                                         new SQLiteParameter("@TypeName",c.ToString()),

                                         new SQLiteParameter("@addDate",DateTime.Now),

                                         new SQLiteParameter("@UpdateTime",DateTime.Now.Date),

                                         new SQLiteParameter("@Time",DateTime.Now.ToShortTimeString()),

                                         new SQLiteParameter("@Comments","Just a Test"+i)

                                         };

                    db.ExecuteNonQuery(sql, parameters);

                }

            }

        }

        public static void ShowData()

        {

            //查询从50条起的20条记录

            string sql = "select * from test3 order by id desc limit 50 offset 20";

            SQLiteDBHelper db = new SQLiteDBHelper("D:\\Demo.db3");

            using (SQLiteDataReader reader = db.ExecuteReader(sql, null))

            {

                while (reader.Read())

                {

                    Console.WriteLine("ID:{0},TypeName{1}", reader.GetInt64(0), reader.GetString(1));

                }

            }

        }

 

    }

}

 

在实际情况中，采用通用类大批量插入数据会有些慢，这是因为在System.Data.SQLite中的操作如果没有指定操作，则会被当做一个事物，如果需要一次性写入大量记录，则建议显式创建一个事物，在这个事务中完成所有的操作比较好，这样的话比每次操作创建一个事物的效率要提升很多。
最终利用VS2008提供的功能，可以看到里面的数据如下： 
需要说明的是在System.Data.SQLite中数据类型的规定不是很严格，从创建Test3表的SQL语句来看，表中addDate、UpdateTime、Time分别是DateTime、Date、Time类型字段，但实际上我们插入的时候没有按照这个规定，最终显示的结果也是尽量遵循数据库字段的定义。
总结
System.Data.SQLite确实是一个非常小巧精悍的数据库，作为对SQLite的封装（SQLite可以在Android等类型的手机上利用Java访问），它依然是体较小，同比性能高、内存消耗小、无需安装仅需一个dll就可以运行的优点（如果在Mobile手机上则需要两个文件），唯一的一个缺点是没有比较的GUI（图形用户界面），不过正因为如此它才得以体积小。
在实际开发中没有图形用户界面可能有些不便，我们可以使用VS来查看和操作数据，我自己也做了一个小东东，便于管理和维护数据，界面如下： 
如果你要开发数据量在10万条以下的应用，我建议你尝试使用一下System.Data.SQLite，它或许是一个不错的选择。