C#通用数据库类
最近在写一个c#的桌面应用,在网上查了半天,也没有合适的数据库访问类,于是自己动手写的一个,以下是关于该类的简单介绍
1、利用DbProviderFactory创建相应的conntion、command、transaction来实现相应的功能,含参数化查询,添加、更新、删除等功能
2、类默认为Sql server数据库,通过传入数据库文件路径,根据文件扩展名来确定数据库类型,用相应的SqlClientFactory.Instance,或OleDbFactory.Instance,创建dbFactory的实例,再用dbFactory的实例创建相应的conntion、command、transaction
3、在添加、更新时,通过控件的Tag保存表字段,根据控件的TabINdex的先后顺序返回对应的字段名和字段值 ,再用string.Join 实现自动创建相应的sql语句和参数化查询;
4、调用示例;grbWorklist是控件的容器,db.GetFieldNames(grbWorklist)获取表字段名的函数,db.GetFieldValues(grbWorklist)获取字段值函数。
dbFactory db=new dbFactory()
int rows=db.InsertRow(“你的查询表”, db.GetFieldNames(grbWorklist), db.GetFieldValues(grbWorklist));
db.Dispose();
//C#通用数据库类`
using System;
using System.Data;
using System.Data.Common;
using System.Data.OleDb;
using System.Data.SqlClient;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Windows.Forms;
namespace WinApp
{
//abstract
public class dbFactory
{
private DbConnection connection; //数据库连结
private DbCommand command; //命令
private DbTransaction transaction; //事务
private DbProviderFactory dbfactory; //数据库提供程序工厂
private string ConnectionString; //数据库连结字串
private Providers Provider;
public System.Collections.Generic.List ColumnTitle = new System.Collections.Generic.List();
public dbFactory(string filePath = “”)
{
string extension = Path.GetExtension(filePath);
switch (extension.ToLower())
{
case ".mdb":
Provider = Providers.OleDb;
this.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Persist Security Info=False;Jet OLEDB:Database Password=love1234love!@(;Data Source=" + filePath;
break;
case ".txt":
Provider = Providers.OleDb;
this.ConnectionString = $"Provider=Microsoft.Jet.OleDb.4.0;Data Source={Path.GetDirectoryName(filePath)};Extended Properties='text;HDR=YES;FMT=Delimited';";
break;
case ".csv":
Provider = Providers.OleDb;
this.ConnectionString = $"Provider=Microsoft.Jet.OLEDB.4.0;Data Source={System.IO.Path.GetDirectoryName(filePath)};Extended Properties='text;HDR=Yes;FMT=Delimited(,)';";
break;
case ".xls":
case ".xlsx":
Provider = Providers.OleDb;
this.ConnectionString = $"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={filePath};Extended Properties='Excel 12.0;HDR=YES;IMEX=1';";
break;
case ".mdf":
case ".ldf":
Provider = Providers.SqlServer;
string sqlConnectionString = $"Data Source=(localdb)\\MSSQLLocalDB;AttachDbFilename={filePath};Integrated Security=True;";
break;
default:
Provider = Providers.SqlServer;
if (LoginInf.ConnTpye == "本地连结")//将大括号的值换成你的数据库配置
this.ConnectionString = $"Data Source={LoginInf.HostName};Initial Catalog={LoginInf.DatabaseName};User ID=sa;Password ={LoginInf.PassWord};Persist Security Info=True;";
else
this.ConnectionString = $"Server ={LoginInf.ServerIP}; Database ={ LoginInf.DatabaseName }; User ID = sa; Password ={ LoginInf.PassWord }; Persist Security Info = True;";
break;
}
switch (Provider)
{
case Providers.SqlServer:
dbfactory = SqlClientFactory.Instance;
break;
case Providers.OleDb:
dbfactory = OleDbFactory.Instance;
break;
}
connection = dbfactory.CreateConnection();
connection.ConnectionString = ConnectionString;
command = connection.CreateCommand();
BeginTransaction();
}
public void OpenConnection()
{
if (connection.State != System.Data.ConnectionState.Open)
{
connection.Open();
}
}
public void CloseConnection()
{
if (connection.State != System.Data.ConnectionState.Closed)
{
connection.Close();
}
}
public void BeginTransaction()
{
OpenConnection();
if (transaction == null)
{
transaction = connection.BeginTransaction();
command.Transaction = transaction;
}
}
public void CommitTransaction()
{
if (transaction != null)
{
transaction.Commit();
transaction = null;
}
}
public void RollbackTransaction()
{
if (transaction != null)
{
transaction.Rollback();
transaction = null;
}
}
//您可以使用以下的 C# 代码来查询未提交的事务并返回结果数据表:
public DataTable GetUncommittedTransactions(string connectionString)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
connection.Open();
SqlCommand command = connection.CreateCommand();
command.CommandText = "SELECT transaction_id, transaction_begin_time FROM sys.dm_tran_active_transactions WHERE transaction_state = 1";
SqlDataAdapter adapter = new SqlDataAdapter(command);
DataTable dataTable = new DataTable();
adapter.Fill(dataTable);
return dataTable;
}
}
public void SetColumsInf(DataTable dt)
{
ColumnTitle.Clear();
for (int i = 0; i < dt.Rows.Count; i++)
{
Columns Col = new Columns();
Col.Index = i;
Col.FieldName = dt.Rows[i]["ColName"].ToString();
Col.ParaName = "@" + dt.Rows[i]["ColName"].ToString();
Col.DbType = dt.Rows[i]["dbType"].ToString();
if (dt.Rows[i]["length"] != DBNull.Value)
Col.Width = Convert.ToDouble(dt.Rows[i]["length"]);
else
Col.Width = 0;
ColumnTitle.Add(Col);
}
}
//private string GetFieldValues(Control parentControl)
//{
// var fieldValues = parentControl.Controls.OfType<TextBox>()
// .Select(c => $"{c.Tag.ToString()} = '{c.Text}'")
// .ToList();
// return string.Join(",", fieldValues);
//}
// 将所有子控件的参数添加到 SqlCommand 中
private void AddParameters(SqlCommand command, Control parentControl)
{
foreach (var control in parentControl.Controls.OfType<TextBox>())
{
command.Parameters.AddWithValue($"@{control.Tag.ToString()}", control.Text);
}
}
public string[] GetColumn(string TableName)
{
connection.Open();
System.Text.StringBuilder str = new System.Text.StringBuilder();
str.Append("select a.TABLE_NAME as 表名,a.COLUMN_NAME as ColName,a.DATA_TYPE as dbType,a.CHARACTER_MAXIMUM_LENGTH length,");
str.Append("a.COLUMN_DEFAULT as 默认值, a.NUMERIC_SCALE as 小数位数,a.DATETIME_PRECISION as 日期精度,a.IS_NULLABLE as 允许Null,");
str.Append("a.NUMERIC_PRECISION as 字段精度,b.value as 说明 from information_schema.COLUMNS as a left join sys.extended_properties as b");
str.Append(" on a.TABLE_NAME = OBJECT_NAME(b.major_id) and a.ORDINAL_POSITION = b.minor_id where a.TABLE_NAME = '");
str.Append(TableName);
str.Append("'");
DbDataReader reader = ExecuteReader(str.ToString());
System.Collections.Generic.List<string> results = new System.Collections.Generic.List<string>();
DataTable dt = null;
dt.Load(reader);
SetColumsInf(dt);
while (reader.Read())
{
results.Add(reader["ColName"].ToString());
}
return results.ToArray();
}
public void AddParameter(string name, object value)
{
DbParameter parameter = command.CreateParameter();
parameter.ParameterName = name;
parameter.Value = value;
command.Parameters.Add(parameter);
}
public int ExecuteNonQuery(string query)
{
command.CommandText = query;
return command.ExecuteNonQuery();
}
public object ExecuteScalar(string query)
{
command.CommandText = query;
return command.ExecuteScalar();
}
public DbDataReader ExecuteReader(string query)
{
command.CommandText = query;
return command.ExecuteReader();
}
//保存图像到数据库
public void SaveImageToDatabase(string imagePath, string tableName, string idColumn, object KeyValue, string imageColumn)
{
Image image = null;
image=Image.FromFile(imagePath);
MemoryStream memoryStream = new MemoryStream();
image.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Png);
byte[] imageData = memoryStream.ToArray();
memoryStream.Dispose();
string query = $"UPDATE {tableName} SET {imageColumn}=@ImageData WHERE {idColumn}=@Id";
command.CommandText = query;
command.Parameters.Clear();
AddParameter("@ImageData", imageData);
AddParameter("@Id", KeyValue);
command.ExecuteNonQuery();
}
//从数据库提取图像并在控件PictureBox上显示
public void LoadImageFromDatabase(int KeyValue, string tableName, string KeyColumn, string imageColumn, System.Windows.Forms.PictureBox pictureBox)
{
string query = $"SELECT {imageColumn} FROM {tableName} WHERE {KeyColumn}=@Id";
command.CommandText = query;
command.Parameters.Clear();
AddParameter("@Id", KeyValue);
byte[] imageData = (byte[])command.ExecuteScalar();
if (imageData != null)
{
MemoryStream memoryStream = new MemoryStream(imageData);
Image image = Image.FromStream(memoryStream);
pictureBox.Image = image;
memoryStream.Dispose();
}
}
public DataTable ExecuteQuery(string query)
{
DbDataAdapter adapter = dbfactory.CreateDataAdapter();
command.CommandText = query;
command.CommandType = CommandType.Text;
adapter.SelectCommand = command;
DataTable dt = new DataTable();
try { adapter.Fill(dt); }
catch (Exception ex)
{
GetFunction.GetMessage(ex.Message);
}
finally
{
command.Parameters.Clear();
}
return dt;
}
public DataTable GetDataTable(string queysql)
{
var dt = new DataTable();
command.CommandText = queysql;
DbDataReader daReader = command.ExecuteReader();
dt.Load(daReader);
return dt;
}
// 利用Tag属性获取所有子控件的对应的字段名(在设计时将控件的Tag等于字段名,并设置TabIndex,以方便自动构建插入、更新的SQL语句)
//可以直接调用insertRow插入一条记录
public string[] GetFieldNames(Control parentControl)
{//使用 LINQ 对容器中的所有控件进行排序,并且排除了 Label 控件。
//你可以在 foreach 循环中遍历这些控件,以按照 TabIndex 的次序依次处理它们。
var controls = parentControl.Controls.Cast<Control>()
.OrderBy(c => c.TabIndex)
.Where(c => !(c is Label));
System.Collections.Generic.List<string> results = new System.Collections.Generic.List<string>();
foreach (Control control in controls)
{
if (control.Tag != null)
{
if (control is TextBox || control is ComboBox)
{
string fieldName = control.Tag.ToString();
results.Add(fieldName);
}
}
}
//fields = fields.TrimEnd(',');
return results.ToArray();
}
// 获取所有子控件的值
public string[] GetFieldValues(Control parentControl)
{
//使用 LINQ 对容器中的所有控件进行排序,并且排除了 Label 控件。
//你可以在 foreach 循环中遍历这些控件,以按照 TabIndex 的次序依次处理它们。
var controls = parentControl.Controls.Cast<Control>()
.OrderBy(c => c.TabIndex)
.Where(c => !(c is Label));
System.Collections.Generic.List<string> results = new System.Collections.Generic.List<string>();
foreach (Control control in controls)
{
if (control.Tag != null)
{
if (control is TextBox || control is ComboBox)
{
string fieldValue = control.Text;
results.Add(fieldValue);
}
}
}
return results.ToArray();
}
public int InsertRow(string tableName, string[] columnNames, object[] values)
{
string columns = string.Join(",", columnNames);
string parameters = string.Join(",", columnNames).Replace(",", ",@");
string query = $"INSERT INTO {tableName} ({columns}) VALUES (@{parameters})";
command.CommandText = query;
command.Parameters.Clear();
for (int i = 0; i < columnNames.Length; i++)
{
AddParameter($"@{columnNames[i]}", values[i]);
}
return command.ExecuteNonQuery();
}
public int DeleteRow(string tableName, string otherTableName, string primaryKeyColumnName, object primaryKeyValue)
{//这里只考虑一个表以tableName的主键为外键的情况,如有多表可以重载该函数,再用数组进行处理如
//public int DeleteRow(string tableName,string[] otherTableName, string primaryKeyColumnName, object[] primaryKeyValue)
if (IsForeignKeyExists(otherTableName, primaryKeyColumnName, primaryKeyValue))
{
throw new Exception("该记录有子项,无法删除");
return -1;
}
else
{
string query = $"DELETE FROM {tableName} WHERE {primaryKeyColumnName}=@Id";
command.CommandText = query;
command.Parameters.Clear();
AddParameter("@Id", primaryKeyValue);
return command.ExecuteNonQuery();
}
}
public int UpdateRowByKey(string tableName, string keyColumnName, string keyValue, string[] columnNames, object[] values)
{
System.Collections.Generic.List<string> updateList = new System.Collections.Generic.List<string>();
for (int i = 0; i < columnNames.Length; i++)
updateList.Add($"{columnNames[i]}=@{columnNames[i]}");
string updateSql = $"UPDATE {tableName} SET {string.Join(",", updateList)} WHERE {keyColumnName} = @key";
AddParameter($"@key", keyValue);
for (int i = 0; i < columnNames.Length; i++)
{
AddParameter($"@{columnNames[i]}", values[i]);
}
return ExecuteNonQuery(updateSql) ;
}
public void ExecuteStoredProcedure(string procedureName)
{
command.CommandType = CommandType.StoredProcedure;
command.CommandText = procedureName;
command.ExecuteNonQuery();
}
public bool HasForeignKey(string tableName, string KeycolumnName, object KeyValue)
{
command.CommandText = $"SELECT COUNT(*) FROM [{tableName}] WHERE [{KeycolumnName}] = @Id";
AddParameter("@Id", KeyValue);
var count = (int)command.ExecuteScalar();
return count > 0;
}
public DbCommand CreateCommand(string commandText, CommandType commandType = CommandType.Text)
{
var cmd = connection.CreateCommand();
cmd.CommandText = commandText;
cmd.CommandType = commandType;
OpenConnection();
return cmd;
}
/// <summary>
/// 判断主键是否被其他表引用
/// </summary>
/// <param name="tableName"></param>
/// <param name="keyName"></param>
/// <param name="value"></param>
/// <returns></returns>
public bool IsForeignKeyExists(string tableName,