转自:http://blog.youkuaiyun.com/gisfarmer/article/details/3648761
看到优快云上不断兄弟姐妹提问关于c#操作Access的问题,于是本人利用闲暇将c#操作Access的方法加以总结,主要解决的问题有:
创建mdb
创建table
读取table内容
查询table中的内容
向table中插入数据
删除table中的记录
向table中插入照片
读取table中的照片等。
另:本人水平有限,不当之处还请斧正。废话少说,开始正题。
文介绍C#访问操作Access数据库的基础知识,并提供一个相关的例程。C#的ADO.NET还不能通过编程方式创建全新的ACCESS(MDB)数据库,所以还只能使用ADOX这个来自COM的链接库来操作。
主要知识点如下:
using System.Data.OleDb;
using System.Data;
连接字符串:String connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=product.mdb";
建立连接:OleDbConnection connection = new OleDbConnection(connectionString);
使用OleDbCommand类来执行Sql语句:
OleDbCommand cmd = new OleDbCommand(sql, connection);
connection.Open();
cmd.ExecuteNonQuery();
1.创建mdb库,例程如下:
需要注意的是:参数mdbPath是mdb的完整路径(不包含表的名称)。例如:D://test.mdb
- //创建mdb
- public static bool CreateMDBDataBase(string mdbPath)
- {
- try
- {
- ADOX.CatalogClass cat = new ADOX.CatalogClass();
- cat.Create("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";");
- cat = null;
- return true;
- }
- catch { return false; }
- }
2.创建具体的表,例程如下:
通常一个mdb的可以包含n个表。下面的程序主要是创建一个table。
- //新建mdb的表
- //mdbHead是一个ArrayList,存储的是table表中的具体列名。
- public static bool CreateMDBTable(string mdbPath,string tableName, ArrayList mdbHead)
- {
- try
- {
- ADOX.CatalogClass cat = new ADOX.CatalogClass();
- string sAccessConnection
- = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath;
- ADODB.Connection cn = new ADODB.Connection();
- cn.Open(sAccessConnection, null, null, -1);
- cat.ActiveConnection = cn;
- //新建一个表
- ADOX.TableClass tbl = new ADOX.TableClass();
- tbl.ParentCatalog = cat;
- tbl.Name = tableName;
- int size = mdbHead.Count;
- for (int i = 0; i < size; i++)
- {
- //增加一个文本字段
- ADOX.ColumnClass col2 = new ADOX.ColumnClass();
- col2.ParentCatalog = cat;
- col2.Name = mdbHead[i].ToString();//列的名称
- col2.Properties["Jet OLEDB:Allow Zero Length"].Value = false;
- tbl.Columns.Append(col2, ADOX.DataTypeEnum.adVarWChar, 500);
- }
- cat.Tables.Append(tbl); //这句把表加入数据库(非常重要)
- tbl = null;
- cat = null;
- cn.Close();
- return true;
- }
- catch { return false; }
- }
3.读取mdb内容(完全读取),例程如下:
本例程返回的是一个DataTable,如需其他格式可以自行转换。
- // 读取mdb数据
- public static DataTable ReadAllData(string tableName, string mdbPath,ref bool success)
- {
- DataTable dt = new DataTable();
- try
- {
- DataRow dr;
- //1、建立连接
- string strConn
- = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";Jet OLEDB:Database Password=haoren";
- OleDbConnection odcConnection = new OleDbConnection(strConn);
- //2、打开连接
- odcConnection.Open();
- //建立SQL查询
- OleDbCommand odCommand = odcConnection.CreateCommand();
- //3、输入查询语句
- odCommand.CommandText = "select * from " + tableName;
- //建立读取
- OleDbDataReader odrReader = odCommand.ExecuteReader();
- //查询并显示数据
- int size = odrReader.FieldCount;
- for (int i = 0; i < size; i++)
- {
- DataColumn dc;
- dc = new DataColumn(odrReader.GetName(i));
- dt.Columns.Add(dc);
- }
- while (odrReader.Read())
- {
- dr = dt.NewRow();
- for (int i = 0; i < size; i++)
- {
- dr[odrReader.GetName(i)] = odrReader[odrReader.GetName(i)].ToString();
- }
- dt.Rows.Add(dr);
- }
- //关闭连接
- odrReader.Close();
- odcConnection.Close();
- success = true;
- return dt;
- }
- catch
- {
- success = false;
- return dt;
- }
- }
4.读取mdb内容(按列读取),例程如下:
columns数组存储的是你要查询的列名称(必须确保mdb表中存在你要的列)
- // 读取mdb数据
- public static DataTable ReadDataByColumns(string mdbPaht,string tableName, string[] columns, ref bool success)
- {
- DataTable dt = new DataTable();
- try
- {
- DataRow dr;
- //1、建立连接
- string strConn
- = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";Jet OLEDB:Database Password=haoren";
- OleDbConnection odcConnection = new OleDbConnection(strConn);
- //2、打开连接
- odcConnection.Open();
- //建立SQL查询
- OleDbCommand odCommand = odcConnection.CreateCommand();
- //3、输入查询语句
- string strColumn = "";
- for (int i = 0; i < columns.Length; i++)
- {
- strColumn += columns[i].ToString() + ",";
- }
- strColumn = strColumn.TrimEnd(',');
- odCommand.CommandText = "select "+strColumn+" from " + tableName;
- //建立读取
- OleDbDataReader odrReader = odCommand.ExecuteReader();
- //查询并显示数据
- int size = odrReader.FieldCount;
- for (int i = 0; i < size; i++)
- {
- DataColumn dc;
- dc = new DataColumn(odrReader.GetName(i));
- dt.Columns.Add(dc);
- }
- while (odrReader.Read())
- {
- dr = dt.NewRow();
- for (int i = 0; i < size; i++)
- {
- dr[odrReader.GetName(i)] = odrReader[odrReader.GetName(i)].ToString();
- }
- dt.Rows.Add(dr);
- }
- //关闭连接
- odrReader.Close();
- odcConnection.Close();
- success = true;
- return dt;
- }
- catch
- {
- success = false;
- return dt;
- }
- }
介绍之前先介绍一个结构体。因为以下函数都要用到这个结构体。
- //普通的节点
- public struct Node
- {
- private string nodeType;
- public string NodeType//表的字段名
- {
- set { nodeType = value; }
- get { return nodeType; }
- }
- private string nodeValue;
- public string NodeValue//具体的值
- {
- set { nodeValue = value; }
- get { return nodeValue; }
- }
- }
- //照片节点
- public struct PictureNode
- {
- private string nodeType;
- public string NodeType//照片的列名
- {
- set { nodeType = value; }
- get { return nodeType; }
- }
- private byte[] nodeValue;
- public byte[] NodeValue//照片的值,注意类型
- {
- set { nodeValue = value; }
- get { return nodeValue; }
- }
- }
具体就用不着多加描述了吧!继续看问题点。
1.向table中插入数据(按行插入,如果需要插入多条请自己组织这个函数就ok了),其中的 insertArray存储的是一系列Node,pictureNode是PictureNode。
- //插入数据
- public static bool InsertRow( string mdbPath, string tableName, ArrayList insertArray,
- PictureNode pictureNode, ref string errinfo)
- {
- try
- {
- //1、建立连接
- string strConn
- = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";Jet OLEDB:Database Password=haoren";
- OleDbConnection odcConnection = new OleDbConnection(strConn);
- //2、打开连接
- odcConnection.Open();
- string str_col = "";
- int size_col = insertArray.Count;
- for (int i = 0; i < size_col; i++)
- {
- Node vipNode = new Node();
- vipNode = (Node)insertArray[i];
- str_col += vipNode.NodeType + ",";
- }
- str_col = str_col.TrimEnd(',');
- int size_row = insertArray.Count;
- string str_row = "";
- for (int i = 0; i < size_row; i++)
- {
- Node vipNode = new Node();
- vipNode = (Node)insertArray[i];
- string v = vipNode.NodeValue.ToString();
- v = DealString(v);
- if (v == "")
- {
- str_row += "null" + ',';
- }
- else
- {
- str_row += "'" + v + "'" + ',';
- }
- }
- str_row = str_row.TrimEnd(',');
- if (pictureNode != null && pictureNode.NodeValue != null)
- {
- str_col += ',' + pictureNode.NodeType;
- str_row += ",@Image";
- }
- string sql = "insert into " + tableName + @" (" + str_col + ") values" + @"(" + str_row + ")";
- OleDbCommand odCommand = new OleDbCommand(sql, odcConnection);
- if (pictureNode != null && pictureNode.NodeValue != null)
- {
- odCommand.Parameters.Add("@Image", OleDbType.VarBinary, pictureNode.NodeValue.Length).Value = pictureNode.NodeValue;
- }
- odCommand.ExecuteNonQuery();
- odcConnection.Close();
- return true;
- }
- catch (Exception err)
- {
- errinfo = err.Message;
- return false;
- }
- }
2.更新一行的数据(与插入类似)
- //更新一行数据
- public static bool UpdateRow(string mdbPath, string tableName,
- Node keyNode,ArrayList insertArray,PictureNode pictureNode, ref string errinfo)
- {
- try
- {
- //1、建立连接
- string strConn
- = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";Jet OLEDB:Database Password=haoren";
- OleDbConnection odcConnection = new OleDbConnection(strConn);
- //2、打开连接
- odcConnection.Open();
- int size = insertArray.Count;
- string str = "";
- for (int i = 0; i < size; i++)
- {
- Node node = new Node();
- node = (Node)insertArray[i];
- string v = node.NodeValue.ToString();
- v = DealString(v);
- str += node.NodeType + " = ";
- if (v == "")
- {
- str += "null" + ',';
- }
- else
- {
- str += "'" + v + "'" + ',';
- }
- }
- str = str.TrimEnd(',');
- if (pictureNode.NodeValue != null)
- {
- str += ',' + pictureNode.NodeType;
- str += " = @Image";
- }
- string sql = "update " + tableName + " set " + str +
- " where " + keyNode.NodeType + " = " + "'" + keyNode.NodeValue + "'";
- OleDbCommand odCommand = new OleDbCommand(sql, odcConnection);
- if (pictureNode.NodeValue != null)
- {
- odCommand.Parameters.Add("@Image", OleDbType.VarBinary, pictureNode.NodeValue.Length).Value = pictureNode.NodeValue;
- }
- odCommand.ExecuteNonQuery();
- odcConnection.Close();
- return true;
- }
- catch (Exception err)
- {
- errinfo = err.Message;
- return false;
- }
- }
3. 插入图片数据.
- //插入图片数据
- public static bool InsertPictureToMDB(string mdbPath, string tableName,Node keyNode,
- PictureNode pictureNode,ref string errinfo)
- {
- try
- {
- //1、建立连接
- string strConn
- = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";Jet OLEDB:Database Password=haoren";
- OleDbConnection odcConnection = new OleDbConnection(strConn);
- //2、打开连接
- odcConnection.Open();
- string sql = @"update " + tableName + " set " + pictureNode.NodeType + "="
- + "@Image where " + keyNode.NodeType + "=" + "'"+keyNode.NodeValue+"'";
- OleDbCommand comm = new OleDbCommand(sql, odcConnection);
- byte[] pic = pictureNode.NodeValue;
- comm.Parameters.Add("@Image", OleDbType.VarBinary, pic.Length).Value = pic;
- comm.ExecuteNonQuery();
- odcConnection.Close();
- return true;
- }
- catch (Exception err)
- {
- errinfo = err.Message;
- return false;
- }
- }
4.修改mdb的一条数据.
- //修改mdb的一条数据
- public static bool UpdateMDBNode( string tableName, Node keyNode,
- Node saveNode, ref string errinfo)
- {
- try
- {
- //1、建立连接
- string strConn
- = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";Jet OLEDB:Database Password=haoren";
- OleDbConnection odcConnection = new OleDbConnection(strConn);
- //2、打开连接
- odcConnection.Open();
- string sql = @"update "+ tableName+" set " + saveNode.NodeType + " = '" + saveNode.NodeValue+
- "' where " + keyNode.NodeType + " = " + "'" + keyNode.NodeValue + "'";
- OleDbCommand comm = new OleDbCommand(sql, odcConnection);
- comm.ExecuteNonQuery();
- odcConnection.Close();
- return true;
- }
- catch (Exception err)
- {
- errinfo = err.Message;
- return false;
- }
- }
5.从mdb中获得照片
- //从mdb中获得照片
- public static byte[] GetImageFromMDB( string tableName, Node keyNode)
- {
- try
- {
- string sql = "Select 照片 From " + tableName +
- " member Where " + keyNode.NodeType + " = "
- + "'" + keyNode.NodeValue + "'";
- string strConn
- = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + mdbPath + ";Jet OLEDB:Database Password=haoren";
- OleDbConnection odcConnection = new OleDbConnection(strConn);
- //2、打开连接
- odcConnection.Open();
- OleDbCommand comm = new OleDbCommand(sql, odcConnection);
- OleDbDataReader sdr = comm.ExecuteReader();
- sdr.Read();
- byte[] pic = (byte[])sdr[0];
- sdr.Close();
- odcConnection.Close();
- return pic;
- }
- catch
- {
- return null;
- }
- }