7

可重现的例子：

sqlite db test3.s3db 有一个名为“MathRec”的表：

name score
Bill 2
Mary 3
John 3

代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;
using System.Data.SQLite;

namespace ConsoleApplication7

{
    class Program
    {
    static void Main(string[] args)
    {

        string fullPath = "C:\\Users\\Desktop\\dataset\\test3.s3db";
        SQLiteConnection conread = new SQLiteConnection("Data Source=" + fullPath);
        conread.Open();

        string selectSQL = "SELECT * FROM MathRec";
        SQLiteCommand selectCommand = new SQLiteCommand(selectSQL, conread);
        SQLiteDataReader dataReader = selectCommand.ExecuteReader();
        DataSet ds = new DataSet();
        DataTable dt = new DataTable("MathRec");
        dt.Load(dataReader);
        ds.Tables.Add(dt);



        // Create a table in the database to receive the information from the DataSet

        string fullPath2 = "C:\\Users\\\\Desktop\\dataset\\test4.s3db";
        SQLiteConnection conwrite = new SQLiteConnection("Data Source=" + fullPath2);
        conwrite.Open();
        SQLiteCommand cmd = new SQLiteCommand(conwrite);
        cmd.CommandText = "DROP TABLE IF EXISTS MathRec";
        cmd.ExecuteNonQuery();
        cmd.CommandText = "CREATE TABLE MathRec(name text , score integer)";
        cmd.ExecuteNonQuery();
        SQLiteDataAdapter adaptor = new SQLiteDataAdapter("SELECT * from MathRec", conwrite);
        adaptor.InsertCommand = new SQLiteCommand("INSERT INTO MathRec  VALUES(:name, :score)", conwrite);
        adaptor.InsertCommand.Parameters.Add("name", DbType.String, 0, "name");
        adaptor.InsertCommand.Parameters.Add("score", DbType.Int32, 0, "score");
        adaptor.Update(ds, "MathRec");



         }

    }
 }

问题：表 MathRec 在 test4.s3db 中创建，列名：name 和 socre，但表是空的，没有插入任何记录。

需要帮助！

请不要问我为什么我只是将一个数据库复制到另一个数据库，因为我正在为一个更大的项目测试代码的一部分，我将在未来的中间步骤中对数据集进行计算。

谢谢！

为了简化问题：

这有效（使用数据表和适配器更新原始 sqlite 表）：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SQLite;
using System.Data;

namespace ConsoleApplication7
{
    class Program
    {
        static void Main(string[] args)
        {
            string fullPath = "C:\\Users\\data\\test.db";
            SQLiteConnection conread = new SQLiteConnection("Data Source=" + fullPath);
            conread.Open();


        SQLiteDataAdapter DB = new SQLiteDataAdapter("SELECT speed, dist FROM Cars2", conread);
        DataSet DS = new DataSet();

        DB.Fill(DS, "NewCars");


        object[] rowVals = new object[2];
        rowVals[0] = 10;
        rowVals[1] = 20;
        DS.Tables["NewCars"].Rows.Add(rowVals);


        DB.InsertCommand = new SQLiteCommand("INSERT INTO Cars2 (speed, dist)  
                                 " + " VALUES (:speed,  :dist)", conread);
        DB.InsertCommand.Parameters.Add("speed", DbType.Double, 0, "speed");
        DB.InsertCommand.Parameters.Add("dist", DbType.Double, 20, "dist");
        DB.Update(DS, "NewCars");



        }
    }
}

这有效（从旧表创建一个新的 sqlite 表）：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SQLite;
using System.Data;

namespace ConsoleApplication7
{
    class Program
    {
        static void Main(string[] args)
        {
            string fullPath = "C:\\Users\\data\\test.db";
            SQLiteConnection conread = new SQLiteConnection("Data Source=" + fullPath);
            conread.Open();


        SQLiteCommand cmd = new SQLiteCommand(conread);
        cmd.CommandText = "DROP TABLE IF EXISTS Cars";
        cmd.ExecuteNonQuery();
        cmd.CommandText = "CREATE TABLE Cars (speed REAL , dist REAL)";
        cmd.ExecuteNonQuery();
        cmd.CommandText = "INSERT INTO Cars SELECT * from DS";
        cmd.ExecuteNonQuery();
        cmd.Dispose();
        }
    }
}

但这是我想要的（使用数据表和适配器在 sqlite 中创建新表）并且不工作：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SQLite;
using System.Data;

namespace ConsoleApplication7
{
    class Program
    {
        static void Main(string[] args)
        {
            string fullPath = "C:\\Users\\data\\test.db";
            SQLiteConnection conread = new SQLiteConnection("Data Source=" + fullPath);
            conread.Open();
    SQLiteDataAdapter DB = new SQLiteDataAdapter("SELECT speed, dist FROM Cars2", conread);
    DataSet DS = new DataSet();

    DB.Fill(DS, "NewCars");


    object[] rowVals = new object[2];
    rowVals[0] = 10;
    rowVals[1] = 20;
    DS.Tables["NewCars"].Rows.Add(rowVals);


   SQLiteDataAdapter DB2 = new SQLiteDataAdapter("SELECT speed, dist FROM Cars3", conread);
    DB2.InsertCommand = new SQLiteCommand("INSERT INTO Cars3 (speed, dist)  
                        " + " VALUES (:speed,  :dist)", conread);
    DB2.InsertCommand.Parameters.Add("speed", DbType.Double, 0, "speed");
    DB2.InsertCommand.Parameters.Add("dist", DbType.Double, 20, "dist");
    DB2.Update(DS, "NewCars");


    }
}
}

请帮忙！！！

4

2 回答 2

5

我找到了答案！

Adapter.Update 只能用于更新数据库中的原始表，不能将数据表保存到新表中。请参阅线程以获得答案：

访问数据库的 C# 数据集

干杯!

于 2013-04-24T14:53:26.840 回答
0

将一个表复制到另一个数据库的最简单方法是将第二个数据库附加到第一个连接，然后直接复制数据：

ATTACH '...\test4.s3db' AS 'test4';
DROP TABLE IF EXISTS test4.MathRec;
CREATE TABLE test4.MathRec(name text , score integer);
INSERT INTO test4.MathRec SELECT * FROM MathRec;

如果您想进行计算，您可以在 SQLSELECT语句中进行计算。如果没有，您必须使用 a 读取数据，SELECT然后INSERT为要写入的每条记录执行一条语句。（在这种情况下，您不需要ATTACH.）

于 2013-04-22T08:52:08.340 回答