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  • C#与SQLite数据库

    1.添加引用 System.Data.SQLite.dll

    2.using System.Data.SQLite;

    3.原理步骤:  

     string path = "c:\mydb.db";
     if (!File.Exists(path))    //1.如果数据库不存在,就创建数据库
     {
       SQLiteConnection.CreateFile(path);
     }
    SQLiteConnection conn = new SQLiteConnection("Data Source="+path);    //2.连接数据库
    conn.Open();    //3.打开数据库
    SQLiteCommand comm = conn.CreateCommand();   //4.创建命令
    comm.CommandText = "SELECT count(*) FROM sqlite_master WHERE type='table' AND name='tablename'"; //5.给命令传sql语句,搜索tablename表是否存在
    SQLiteDataReader reader = comm.ExecuteReader();    //6.执行命令
    reader.Read();    //7.获取结果的"指针"
    int num = reader.GetInt32(0);  //8.第一行数据的第0个值
    reader.Close();    //关闭reader,如果不关闭,下面使用comm命令执行sql语句会报错
    conn.Close();   //关闭连接

    将txt中的数据写入到sqlite数据库中的函数。//参数file是txt文件的路径名

     static void TxtToSQLite(string file)
            {
                string path = "c:\mydb.db";
                string sqlData = "(";
                if (!File.Exists(path))
                {
                    SQLiteConnection.CreateFile(path);
                }
                SQLiteConnection conn = new SQLiteConnection("Data Source=" + path);
                conn.Open();
                SQLiteCommand comm = conn.CreateCommand();
    
                StreamReader sReader = new StreamReader(file);
                string strLine = sReader.ReadLine();  //读取文件的第一行            
                string tableName = "year" + strLine.Substring(24, 4);
                //如果数据库中没有这个表就创建一个
                comm.CommandText = "CREATE TABLE IF NOT EXISTS " + tableName + "(ID integer, altitude double, longitude double, p4 integer, p5 integer, p6 integer, p7 integer, p8 integer, p9 integer, p10 integer, p11 integer, p12 integer, p13 integer)";
                comm.ExecuteNonQuery();
                while (strLine != null)
                {
                    while (strLine.IndexOf("  ")!=-1)
                    {                   
                        strLine = strLine.Replace("  ", " ");
                    }
                    strLine = strLine.Replace(" ", ",");
                    sqlData = sqlData+strLine+"),(";
                    strLine = sReader.ReadLine();
                }
                sqlData = sqlData.Remove(sqlData.Length - 2, 2);
                comm.CommandText = "INSERT INTO " + tableName + " VALUES " + sqlData ;    
                try
                {
                    comm.ExecuteNonQuery();
                }
                catch (System.Exception ex)
                {
                    Debug.WriteLine(ex.Message);
                }            
                sReader.Close();
                conn.Close();
            }

    txt数据格式:

    说明:sqlite_master 、 SQLITE_TEMP_MASTER(存储临时表)

      获得所有表的列表:

    SELECT name FROM (SELECT * FROM sqlite_master UNION ALL SELECT * FROM sqlite_temp_master) WHERE type=tableORDER BY name

     下载:System.Data.SQLite.dll   http://files.cnblogs.com/files/lwngreat/System.Data.SQLite.rar

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  • 原文地址:https://www.cnblogs.com/lwngreat/p/4717063.html
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