3

我正在尝试从一个 Access 数据库文件中获取表，将它们添加到另一个具有完全相同结构但具有不同信息的 Access 数据库文件中。我需要覆盖任何现有的表。我的项目几乎完成了，这是我的最后一堵砖墙。

我正在使用一个名为 DatabaseHandling.cs 的单独类文件来处理 Access 数据库文件。

这是我当前的全部 DatabaseHandling.cs 代码。暂时保持最新状态。

代码：

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.OleDb;
using System.IO;
using System.Linq;
using System.Text;

namespace LCR_ShepherdStaffupdater_1._0
{
    public class DatabaseHandling
    {
        static DataTable datatableB = new DataTable();
        static DataTable datatableA = new DataTable();
        public static DataSet datasetA = new DataSet();
        public static DataSet datasetB = new DataSet();
        static OleDbDataAdapter adapterA = new OleDbDataAdapter();
        static OleDbDataAdapter adapterB = new OleDbDataAdapter();
        static string connectionstringA = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + Settings.getfilelocationA();
        static string connectionstringB = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + Settings.getfilelocationB();
        static OleDbConnection dataconnectionB = new OleDbConnection(connectionstringB);
        static OleDbConnection dataconnectionA = new OleDbConnection(connectionstringA);
        static DataTable tableListA;
        static DataTable tableListB;

        static public void addTableA(string table, bool addtoDataSet)
        {
            dataconnectionA.Open();
            datatableA = new DataTable(table);
            try
            {
                OleDbCommand commandselectA = new OleDbCommand("SELECT * FROM [" + table + "]", dataconnectionA);
                adapterA.SelectCommand = commandselectA;
                adapterA.Fill(datatableA);
            }
            catch
            {
                Logging.updateLog("Error: Tried to get " + table + " from DataSetA. Table doesn't exist!", true, false, false);
            }

            if (addtoDataSet == true)
            {
                datasetA.Tables.Add(datatableA);
                Logging.updateLog("Added DataTableA: " + datatableA.TableName.ToString() + " Successfully!", false, false, false);
            }

            dataconnectionA.Close();
        }

        static public void addTableB(string table, bool addtoDataSet)
        {
            dataconnectionB.Open();
            datatableB = new DataTable(table);

            try
            {
                OleDbCommand commandselectB = new OleDbCommand("SELECT * FROM [" + table + "]", dataconnectionB);
                adapterB.SelectCommand = commandselectB;
                adapterB.Fill(datatableB);
            }
            catch
            {
                Logging.updateLog("Error: Tried to get " + table + " from DataSetB. Table doesn't exist!", true, false, false);
            }



            if (addtoDataSet == true)
            {
                datasetB.Tables.Add(datatableB);
                Logging.updateLog("Added DataTableB: " + datatableB.TableName.ToString() + " Successfully!", false, false, false);
            }

            dataconnectionB.Close();
        }

        static public string[] getTablesA(string connectionString)
        {
            dataconnectionA.Open();
            tableListA = dataconnectionA.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new Object[] { null, null, null, "TABLE" });
            string[] stringTableListA = new string[tableListA.Rows.Count];

            for (int i = 0; i < tableListA.Rows.Count; i++)
            {
                stringTableListA[i] = tableListA.Rows[i].ItemArray[2].ToString();
            }
            dataconnectionA.Close();
            return stringTableListA;
        }

        static public string[] getTablesB(string connectionString)
        {
            dataconnectionB.Open();
            tableListB = dataconnectionB.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, new Object[] { null, null, null, "TABLE" });
            string[] stringTableListB = new string[tableListB.Rows.Count];

            for (int i = 0; i < tableListB.Rows.Count; i++)
            {
                stringTableListB[i] = tableListB.Rows[i].ItemArray[2].ToString();
            }
            dataconnectionB.Close();
            return stringTableListB;
        }

        static public void createDataSet()
        {

            string[] tempA = getTablesA(connectionstringA);
            string[] tempB = getTablesB(connectionstringB);
            int percentage = 0;
            int maximum = (tempA.Length + tempB.Length);

            Logging.updateNotice("Loading Tables...");
            Logging.updateLog("Started Loading File A", false, true, false);
            for (int i = 0; i < tempA.Length ; i++)
            {
                if (!datasetA.Tables.Contains(tempA[i]))
                {
                    addTableA(tempA[i], true);
                    percentage++;
                    Logging.loadStatus(percentage, maximum);
                }
                else
                {
                    datasetA.Tables.Remove(tempA[i]);
                    addTableA(tempA[i], true);
                    percentage++;
                    Logging.loadStatus(percentage, maximum);
                }
            }
            Logging.updateLog("Finished loading File A", false, true, false);
            Logging.updateLog("Started loading File B", false, true, false);
            for (int i = 0; i < tempB.Length ; i++)
            {
                if (!datasetB.Tables.Contains(tempB[i]))
                {
                    addTableB(tempB[i], true);
                    percentage++;
                    Logging.loadStatus(percentage, maximum);
                }
                else
                {
                    datasetB.Tables.Remove(tempB[i]);
                    addTableB(tempB[i], true);
                    percentage++;
                    Logging.loadStatus(percentage, maximum);
                }
            }
            Logging.updateLog("Finished loading File B", false, true, false);


        }

        static public DataTable getDataTableA()
        {
            datatableA = datasetA.Tables[Settings.textA];

            return datatableA;
        }
        static public DataTable getDataTableB()
        {
            datatableB = datasetB.Tables[Settings.textB];
            return datatableB;
        }

        static public DataSet getDataSetA()
        {
            return datasetA;
        }

        static public DataSet getDataSetB()
        {
            return datasetB;
        }

        static public void InitiateCopyProcessA()
        {
            DataSet tablesA;
            tablesA = DatabaseHandling.getDataSetA();

                foreach (DataTable table in tablesA.Tables)
                {
                    OverwriteTable(table, table.TableName);
                    Logging.updateLog("Copied " + table.TableName + " successfully.", false, true, false);
                }

        }

        static void OverwriteTable(DataTable sourceTable, string tableName)
        {
            using (var destConn = new OleDbConnection(connectionstringA))
            using (var destCmd = new OleDbCommand(tableName, destConn) { CommandType = CommandType.TableDirect })
            using (var destDA = new OleDbDataAdapter(destCmd))
            {
                // Since we're using a single table, we can have the CommandBuilder
                // generate the appropriate INSERT and DELETE SQL statements
                using (var destCmdB = new OleDbCommandBuilder(destDA))
                {
                    destCmdB.QuotePrefix = "["; // quote reserved column names
                    destCmdB.QuotePrefix = "]";
                    destDA.DeleteCommand = destCmdB.GetDeleteCommand();
                    destDA.InsertCommand = destCmdB.GetInsertCommand();

                    // Get rows from destination, and delete them
                    var destTable = new DataTable();
                    destDA.Fill(destTable);
                    foreach (DataRow dr in destTable.Rows)
                    {
                        dr.Delete();
                    }
                    destDA.Update(destTable);

                    // Set rows from source as Added, so the DataAdapter will insert them
                    foreach (DataRow dr in sourceTable.Rows)
                    {
                        dr.SetAdded();
                    }
                    destDA.Update(sourceTable);
                }
            }
        }



        }          
    }

我只是想获取内存中的数据表并将其写入 .MDB 文件。我已经尝试这样做了 30 多个小时。

最新编辑：

好的，添加了新代码。我收到一个新的运行时错误：FROM 子句中的语法错误。

代码：

static public void InitiateCopyProcessA()
{
    DataSet tablesA;
    tablesA = DatabaseHandling.getDataSetA();

        foreach (DataTable table in tablesA.Tables)
        {
            OverwriteTable(table, table.TableName);
            Logging.updateLog("Copied " + table.TableName + " successfully.", false, true, false);
        }

}

static void OverwriteTable(DataTable sourceTable, string tableName)
{
    using (var destConn = new OleDbConnection(connectionstringA))
    using (var destCmd = new OleDbCommand(tableName, destConn) { CommandType = CommandType.TableDirect })
    using (var destDA = new OleDbDataAdapter(destCmd))
    {
        // Since we're using a single table, we can have the CommandBuilder
        // generate the appropriate INSERT and DELETE SQL statements
        using (var destCmdB = new OleDbCommandBuilder(destDA))
        {
            destCmdB.QuotePrefix = "["; // quote reserved column names
            destCmdB.QuotePrefix = "]";
            destDA.DeleteCommand = destCmdB.GetDeleteCommand();
            destDA.InsertCommand = destCmdB.GetInsertCommand();

            // Get rows from destination, and delete them
            var destTable = new DataTable();
            destDA.Fill(destTable);
            foreach (DataRow dr in destTable.Rows)
            {
                dr.Delete();
            }
            destDA.Update(destTable);

            // Set rows from source as Added, so the DataAdapter will insert them
            foreach (DataRow dr in sourceTable.Rows)
            {
                dr.SetAdded();
            }
            destDA.Update(sourceTable); // !!! Run-time error: Syntax error in FROM clause. !!!
        }
    }
}

再一次，它不起作用。如果您需要更多信息，请告诉我。

4

3 回答 3

1

我觉得你并没有真正了解整个 DataTable/DataRow 的事情。您会看到，在数据库中，您并没有真正使用表，而是使用行。如果您想用 TableA 的行“覆盖”TableB，您首先要删除 TableB 中的所有行，然后插入 TableA 中所有行的副本。

假设目标表已经存在，您可以通过从 1 个源填充来进行插入，然后将行设置为已添加。然后，DataAdapter 将为每个添加的行运行 SQL 插入命令。

static void CopyTable(string sourceConnectionString, string destinationConnectionString, string tableName) {
    // Get rows from source
    var sourceTable = new DataTable();
    using (var sourceConn = new OleDbConnection(sourceConnectionString))
    using (var sourceCmd = new OleDbCommand(tableName, sourceConn) { CommandType = CommandType.TableDirect })
    using (var sourceDA = new OleDbDataAdapter(sourceCmd)) {
        sourceDA.Fill(sourceTable);
    }

    OverwriteTable(sourceTable, destinationConnectionString, tableName);
}

static void OverwriteTable(DataTable sourceTable, string destinationConnectionString, string tableName) {
    using (var destConn = new OleDbConnection(destinationConnectionString))
    using (var destCmd = new OleDbCommand(tableName, destConn) { CommandType = CommandType.TableDirect })
    using (var destDA = new OleDbDataAdapter(destCmd)) {
        // Since we're using a single table, we can have the CommandBuilder
        // generate the appropriate INSERT and DELETE SQL statements
        using (var destCmdB = new OleDbCommandBuilder(destDA)) {
            destCmdB.QuotePrefix = "["; // quote reserved column names
            destCmdB.QuoteSuffix = "]";
            destDA.DeleteCommand = destCmdB.GetDeleteCommand();
            destDA.InsertCommand = destCmdB.GetInsertCommand();

            // Get rows from destination, and delete them
            var destTable = new DataTable();
            destDA.Fill(destTable);
            foreach (DataRow dr in destTable.Rows) {
                dr.Delete();
            }
            destDA.Update(destTable);

            // Set rows from source as Added, so the DataAdapter will insert them
            foreach (DataRow dr in sourceTable.Rows) {
               dr.SetAdded(); 
            }
            destDA.Update(sourceTable);
        }
    }    
}

编辑：将 OverwriteTable 拆分为不同的方法以容纳您的内存数据表。还为您保留的 Year 和 Month 列名称在生成的 Sql 语句周围添加了引号。移动了由Bendewey修复的 CommandBuilder的处置。

于 2009-02-06T15:16:53.610 回答
1

尝试更换

using (var destCmdB = new OleDbCommandBuilder(destDA)) 
{            
    destDA.DeleteCommand = destCmdB.GetDeleteCommand();            
    destDA.InsertCommand = destCmdB.GetInsertCommand();        
}

和

destDA.InsertCommand = new OleDbCommand("INSERT INTO `AdminUsers` (`UserName`, `Password`) VALUES (?, ?)");
destDA.DeleteCommand = new OleDbCommand("DELETE FROM `AdminUsers` WHERE (`ID` = ?)");
destDA.UpdateCommand = new OldDbCommand("UPDATE `AdminUsers` SET `UserName` = ?, `Password` = ? WHERE (`ID` = ?)");

查询对您的表结构有效的位置。

于 2009-02-06T15:50:31.220 回答
1

@Mark Brackett 真的很接近你没有 DeleteCommand 的原因是因为 OleDbCommandBuilder 正在处理，所以移动那个括号，你应该很好。

static void CopyTable(string sourceConnectionString, string destinationConnectionString, string tableName)
{
// Get rows from source    
var sourceTable = new DataTable();
using (var sourceConn = new OleDbConnection(sourceConnectionString))
using (var sourceCmd = new OleDbCommand(tableName, sourceConn) {CommandType = CommandType.TableDirect})
using (var sourceDA = new OleDbDataAdapter(sourceCmd))
{
    sourceDA.Fill(sourceTable);
}
using (var destConn = new OleDbConnection(destinationConnectionString))
using (var destCmd = new OleDbCommand(tableName, destConn) {CommandType = CommandType.TableDirect})
using (var destDA = new OleDbDataAdapter(destCmd))
{
    // Since we're using a single table, we can have the CommandBuilder        
    // generate the appropriate INSERT and DELETE SQL statements        
    using (var destCmdB = new OleDbCommandBuilder(destDA))
    {
        destDA.DeleteCommand = destCmdB.GetDeleteCommand();
        destDA.InsertCommand = destCmdB.GetInsertCommand();

        // Get rows from destination, and delete them        
        var destTable = new DataTable();
        destDA.Fill(destTable);
        foreach (DataRow dr in destTable.Rows)
        {
            dr.Delete();
        }
        destDA.Update(destTable);
        // Set rows from source as Added, so the DataAdapter will insert them        
        foreach (DataRow dr in sourceTable.Rows)
        {
            dr.SetAdded();
        }
        destDA.Update(sourceTable);
    }
}

更新

试试这个异常代码

static public void InitiateCopyProcessA()
{
    DataSet tablesA;
    tablesA = DatabaseHandling.getDataSetA();
    int i = 0;
    string tableName = "";
    try
    {
        foreach (DataTable table in tablesA.Tables)
        {
            tableName = table.TableName;  // for debugging the exception
            CopyTable(connectionstringA, connectionstringB, table.TableName);
        }
    }
    catch(Exception ex)
    {
        throw new Exception("Error updating " + tableName, ex);
    }
}

更新

尝试改变

// Set rows from source as Added, so the DataAdapter will insert them                
foreach (DataRow dr in sourceTable.Rows)        
{            
    dr.SetAdded();        
}

到

// only add the first row.
sourceTable.Rows[0].SetAdded()

我很想知道它是否只是抛出错误的一行，或者它是否是查询。我的想法是其中一行具有时髦的价值

于 2009-02-06T16:37:07.537 回答