SQLite.Net操作类

为了便于使用SQLite.Net，参照微软企业库中数据组件的写法写了这个类，无非就是为了便于使用。

下面是代码：

 

代码

using  System;
using  System.Data;
using  System.Data.Common;
using  System.Data.SQLite;
using  System.IO;

namespace  IdentifyCode.Data
{
     public   class  Database
    {
         ///   <summary>
         ///    构造函数
         ///   </summary>
         ///   <param name="dataSource"> 数据文件 </param>
         public  Database( string  dataSource)
            :  this (dataSource,  false ,  true )
        {
        }

         ///   <summary>
         ///  构造函数
         ///   </summary>
         ///   <param name="dataSource"> 数据文件 </param>
         ///   <param name="readOnly"> 是否只读 </param>
         ///   <param name="pooling"> 是否使用连接池 </param>
         public  Database( string  dataSource,  bool  readOnly,  bool  pooling)
        {
             if  ( ! File.Exists(dataSource))
            {
                SQLiteConnection.CreateFile(dataSource);
            }
            SQLiteConnectionStringBuilder sb  =   new  SQLiteConnectionStringBuilder
            {
                DataSource  =  dataSource,
                Version  =   3 ,
                ReadOnly  =  readOnly,
                Pooling  =  pooling
            };
            ConnectionString  =  sb.ToString();
        }

         ///   <summary>
         ///    连接字符串
         ///   </summary>
         public   static   string  ConnectionString {  get ;  private   set ; }

         ///   <summary>
         ///    获取Sql语句命令
         ///   </summary>
         ///   <param name = "query"></param>
         ///   <returns></returns>
         public  DbCommand GetSqlStringCommand( string  query)
        {
             if  (String.IsNullOrEmpty(query))
            {
                 throw   new  ArgumentException( " 查询字符串不能为空。 " );
            }

            DbCommand command  =   new  SQLiteCommand(query) { CommandType  =  CommandType.Text };
             return  command;
        }

         public  DbCommand GetSqlStringCommand( string  query, DbTransaction transaction)
        {
            DbCommand command  =  GetSqlStringCommand(query);
            command.Transaction  =  transaction;
             return  command;
        }

         public  SQLiteTransaction GetTransaction()
        {
            SQLiteConnection conn  =   new  SQLiteConnection(ConnectionString);
             if  (conn.State  !=  ConnectionState.Open)
            {
                conn.Open();
            }
             return  conn.BeginTransaction();
        }

         ///   <summary>
         ///    添加参数
         ///   </summary>
         ///   <param name = "command"></param>
         ///   <param name = "dbType"></param>
         public   void  AddInParameter(DbCommand command, DbType dbType)
        {
            command.Parameters.Add( new  SQLiteParameter(dbType));
        }

         ///   <summary>
         ///    添加参数
         ///   </summary>
         ///   <param name = "command"></param>
         ///   <param name = "dbType"></param>
         ///   <param name = "value"></param>
         public   void  AddInParameter(DbCommand command, DbType dbType,  object  value)
        {
             if  (value  ==   null )
            {
                value  =   " null " ;
            }
            command.Parameters.Add( new  SQLiteParameter(dbType) { Value  =  value });
        }

         ///   <summary>
         ///    执行
         ///   </summary>
         ///   <param name = "command"></param>
         ///   <returns></returns>
         public   long  ExecuteNonQuery(DbCommand command)
        {
             // 如果包含事务，就执行返回，不管连接
             if  (command.Transaction  !=   null )
            {
                 return  command.ExecuteNonQuery();
            }

             using  (SQLiteConnection conn  =   new  SQLiteConnection(ConnectionString))
            {
                 if  (conn.State  !=  ConnectionState.Open)
                {
                    conn.Open();
                }
                command.Connection  =  conn;
                 return  command.ExecuteNonQuery();
            }
        }

         ///   <summary>
         ///    执行
         ///   </summary>
         ///   <param name = "command"></param>
         ///   <returns></returns>
         public  DbDataReader ExecuteReader(DbCommand command)
        {
            SQLiteConnection conn  =   new  SQLiteConnection(ConnectionString);
             try
            {
                 if  (conn.State  !=  ConnectionState.Open)
                {
                    conn.Open();
                }
                command.Connection  =  conn;
                 return  command.ExecuteReader();
            }
             catch
            {
                 if  (conn.State  !=  ConnectionState.Closed)
                {
                    conn.Close();
                }
                 throw ;
            }
        }

         public   long  ExecuteScalar(DbCommand command)
        {
             using  (SQLiteConnection conn  =   new  SQLiteConnection(ConnectionString))
            {
                 if  (conn.State  !=  ConnectionState.Open)
                {
                    conn.Open();
                }
                command.Connection  =  conn;
                 object  obj  =  command.ExecuteScalar();
                 long  l  =  ( long )obj;
                 return  l;
            }
        }
    }
}

 

 

使用方法

1.带事务：

 

代码

Database db  =   new  Database(dataSource);
using  (SQLiteTransaction tran  =  db.GetTransaction())
{
     using  (DbCommand command  =  db.GetSqlStringCommand(sqlString, tran))
    {
         foreach  (Entity entity  in  list)
        {
            db.AddInParameter(command, DbType.String, ...);
            ...

            db.ExecuteNonQuery(command);
            command.Parameters.Clear();
        }

        tran.Commit();
    }
}

 

2.不带事务：

 

代码

Database db  =   new  Database(dataSource);
using  (DbCommand command  =  db.GetSqlStringCommand(sqlString))
{
     foreach  (Entity entity  in  list)
    {
        db.AddInParameter(command, DbType.String, ...);
        ...

        db.ExecuteNonQuery(command);
        command.Parameters.Clear();
    }
}

 

 

因为SQLite默认对每个操作打开一个事务，所以如果不声明事务的话，对于任何影响超过1行数据的操作都将会消耗非常长的时间。