using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Data.SQLite;
using System.Configuration;
using System.Text;
//注意事项
//1. @@IDENTITY LAST_INSERT_ROWID()
//2. SELECT cn = COUNT(*) FROM ...
SELECT COUNT(*) cn FROM ...
//3. LIMIT startIndex,itemCn
这儿的startIndex是从0开始的，而ROW_NUMBER()是从1开始的
//4. sqlite中没有SELECT TOP,用LIMIT即可
//5. SQLite自增字段，如果在事务中插入数据失败，并不会占用增长后的id，而sql server中对应的id将无效
//6.
SQLite中没有GETDATE日期函数，在类中加入参数如下DbType.DateTime,DateTime.Now.ToString("s")
//7. SQLite支持REPLACE INTO语法,sql server 2008中支持merge to
namespace
Common.SqliteCe
{
public class
SQLiteHelper
{
//数据库连接字符串(web.config来配置)，可以动态更改SQLString支持多数据库.
public static string DataBasePath
= @"\Database\Mobile.s3db";
public
static string connectionString = "Data Source=" + DataBasePath +
";Version=3;Pooling=False;Max Pool Size=100;";
public SQLiteHelper() { }
#region 公用方法
public static int GetMaxID(string
FieldName, string TableName)
{
string strsql = "select max(" + FieldName + ")+1 from " + TableName;
object obj = GetSingle(strsql);
if (obj ==
null)
{
return 1;
}
else
{
return int.Parse(obj.ToString());
}
}
public static bool Exists(string
strSql)
{
object obj = GetSingle(strSql);
int cmdresult;
if
((Object.Equals(obj, null)) || (Object.Equals(obj,
System.DBNull.Value)))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if
(cmdresult ==
0)
{
return false;
}
else
{
return true;
}
}
public static bool Exists(string
strSql, params SQLiteParameter[]
cmdParms)
{
object obj = GetSingle(strSql, cmdParms);
int cmdresult;
if
((Object.Equals(obj, null)) || (Object.Equals(obj,
System.DBNull.Value)))
{
cmdresult = 0;
}
else
{
cmdresult = int.Parse(obj.ToString());
}
if
(cmdresult ==
0)
{
return false;
}
else
{
return true;
}
}
#endregion
#region 执行简单SQL语句
///
<summary>
///
执行SQL语句，返回影响的记录数
///
</summary>
/// <param
name="SQLString">SQL语句</param>
///
<returns>影响的记录数</returns>
public static int ExecuteSql(string
SQLString)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand(SQLString,
connection))
{
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException
E)
{
connection.Close();
throw new Exception(E.Message);
}
}
}
}
///
<summary>
///
执行SQL语句，设置命令的执行等待时间
///
</summary>
/// <param
name="SQLString"></param>
/// <param
name="Times"></param>
///
<returns></returns>
public static int ExecuteSqlByTime(string SQLString, int
Times)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand(SQLString,
connection))
{
try
{
connection.Open();
cmd.CommandTimeout = Times;
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException
E)
{
connection.Close();
throw new Exception(E.Message);
}
}
}
}
///
<summary>
///
执行多条SQL语句，实现数据库事务。
///
</summary>
/// <param
name="SQLStringList">多条SQL语句</param>
public static void
ExecuteSqlTran(ArrayList
SQLStringList)
{
using
(SQLiteConnection conn = new
SQLiteConnection(connectionString))
{
conn.Open();
SQLiteCommand cmd = new SQLiteCommand();
cmd.Connection = conn;
SQLiteTransaction tx = conn.BeginTransaction();
cmd.Transaction = tx;
try
{
for (int n = 0; n < SQLStringList.Count;
n++)
{
string strsql = SQLStringList[n].ToString();
if (strsql.Trim().Length >
1)
{
cmd.CommandText = strsql;
cmd.ExecuteNonQuery();
}
}
tx.Commit();
}
catch (System.Data.SQLite.SQLiteException
E)
{
tx.Rollback();
throw new Exception(E.Message);
}
}
}
///
<summary>
///
执行带一个存储过程参数的的SQL语句。
///
</summary>
/// <param
name="SQLString">SQL语句</param>
/// <param
name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
///
<returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString, string
content)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand(SQLString, connection);
SQLiteParameter myParameter = new SQLiteParameter("@content", DbType.String);
myParameter.Value = content;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException
E)
{
throw new Exception(E.Message);
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
///
<summary>
///
执行带一个存储过程参数的的SQL语句。
///
</summary>
/// <param
name="SQLString">SQL语句</param>
/// <param
name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
///
<returns>影响的记录数</returns>
public static object ExecuteSqlGet(string SQLString, string
content)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand(SQLString, connection);
SQLiteParameter myParameter = new SQLiteParameter("@content", DbType.String);
myParameter.Value = content;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
object obj = cmd.ExecuteScalar();
if ((Object.Equals(obj, null)) || (Object.Equals(obj,
System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SQLite.SQLiteException
E)
{
throw new Exception(E.Message);
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
///
<summary>
///
向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
///
</summary>
/// <param
name="strSQL">SQL语句</param>
/// <param
name="fs">图像字节,数据库的字段类型为image的情况</param>
///
<returns>影响的记录数</returns>
public static int ExecuteSqlInsertImg(string strSQL, byte[]
fs)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
SQLiteParameter myParameter = new SQLiteParameter("@fs", DbType.Binary);
myParameter.Value = fs;
cmd.Parameters.Add(myParameter);
try
{
connection.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SQLite.SQLiteException
E)
{
throw new Exception(E.Message);
}
finally
{
cmd.Dispose();
connection.Close();
}
}
}
///
<summary>
///
执行一条计算查询结果语句，返回查询结果（object）。
///
</summary>
/// <param
name="SQLString">计算查询结果语句</param>
///
<returns>查询结果（object）</returns>
public static object GetSingle(string
SQLString)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new SQLiteCommand(SQLString,
connection))
{
try
{
connection.Open();
object obj = cmd.ExecuteScalar();
if ((Object.Equals(obj, null)) || (Object.Equals(obj,
System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SQLite.SQLiteException
e)
{
connection.Close();
throw new Exception(e.Message);
}
}
}
}
///
<summary>
///
执行查询语句，返回SQLiteDataReader(使用该方法切记要手工关闭SQLiteDataReader和连接)
/// </summary>
/// <param
name="strSQL">查询语句</param>
///
<returns>SQLiteDataReader</returns>
public static SQLiteDataReader ExecuteReader(string
strSQL)
{
SQLiteConnection connection = new SQLiteConnection(connectionString);
SQLiteCommand cmd = new SQLiteCommand(strSQL, connection);
try
{
connection.Open();
SQLiteDataReader myReader = cmd.ExecuteReader();
return myReader;
}
catch
(System.Data.SQLite.SQLiteException
e)
{
throw new Exception(e.Message);
}
//finally //不能在此关闭，否则，返回的对象将无法使用
//{
// cmd.Dispose();
// connection.Close();
//}
}
///
<summary>
///
执行查询语句，返回DataSet
///
</summary>
/// <param
name="SQLString">查询语句</param>
///
<returns>DataSet</returns>
public static DataSet Query(string
SQLString)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
command.Fill(ds, "ds");
}
catch (System.Data.SQLite.SQLiteException
ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
public static DataSet Query(string
SQLString, string TableName)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
command.Fill(ds, TableName);
}
catch (System.Data.SQLite.SQLiteException
ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
///
<summary>
///
执行查询语句，返回DataSet,设置命令的执行等待时间
///
</summary>
/// <param
name="SQLString"></param>
/// <param
name="Times"></param>
///
<returns></returns>
public static DataSet Query(string
SQLString, int Times)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
DataSet ds = new DataSet();
try
{
connection.Open();
SQLiteDataAdapter command = new SQLiteDataAdapter(SQLString, connection);
command.SelectCommand.CommandTimeout = Times;
command.Fill(ds, "ds");
}
catch (System.Data.SQLite.SQLiteException
ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
#endregion
#region 执行带参数的SQL语句
///
<summary>
///
执行SQL语句，返回影响的记录数
///
</summary>
/// <param
name="SQLString">SQL语句</param>
///
<returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString, params SQLiteParameter[]
cmdParms)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new
SQLiteCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
int rows = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return rows;
}
catch (System.Data.SQLite.SQLiteException
E)
{
throw new Exception(E.Message);
}
}
}
}
///
<summary>
///
执行多条SQL语句，实现数据库事务。
///
</summary>
/// <param
name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SQLiteParameter[]）</param>
public static void ExecuteSqlTran(Hashtable
SQLStringList)
{
using
(SQLiteConnection conn = new
SQLiteConnection(connectionString))
{
conn.Open();
using (SQLiteTransaction trans =
conn.BeginTransaction())
{
SQLiteCommand cmd = new SQLiteCommand();
try
{
//循环
foreach (DictionaryEntry myDE in
SQLStringList)
{
string cmdText = myDE.Key.ToString();
SQLiteParameter[] cmdParms = (SQLiteParameter[])myDE.Value;
PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
trans.Commit();
}
}
catch
{
trans.Rollback();
throw;
}
}
}
}
///
<summary>
///
执行一条计算查询结果语句，返回查询结果（object）。
///
</summary>
/// <param
name="SQLString">计算查询结果语句</param>
///
<returns>查询结果（object）</returns>
public static object GetSingle(string SQLString, params SQLiteParameter[]
cmdParms)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
using (SQLiteCommand cmd = new
SQLiteCommand())
{
try
{
PrepareCommand(cmd, connection, null, SQLString,
cmdParms);
object obj =
cmd.ExecuteScalar();
cmd.Parameters.Clear();
if ((Object.Equals(obj, null)) || (Object.Equals(obj,
System.DBNull.Value)))
{
return
null;
}
else
{
return
obj;
}
}
catch (System.Data.SQLite.SQLiteException
e)
{
throw new
Exception(e.Message);
}
}
}
}
///
<summary>
///
执行查询语句，返回SQLiteDataReader
(使用该方法切记要手工关闭SQLiteDataReader和连接)
/// </summary>
/// <param
name="strSQL">查询语句</param>
///
<returns>SQLiteDataReader</returns>
public static SQLiteDataReader ExecuteReader(string SQLString, params
SQLiteParameter[] cmdParms)
{
SQLiteConnection connection = new SQLiteConnection(connectionString);
SQLiteCommand cmd = new SQLiteCommand();
try
{
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
SQLiteDataReader myReader = cmd.ExecuteReader();
cmd.Parameters.Clear();
return myReader;
}
catch
(System.Data.SQLite.SQLiteException
e)
{
throw new Exception(e.Message);
}
//finally //不能在此关闭，否则，返回的对象将无法使用
//{
// cmd.Dispose();
// connection.Close();
//}
}
///
<summary>
///
执行查询语句，返回DataSet
///
</summary>
/// <param
name="SQLString">查询语句</param>
///
<returns>DataSet</returns>
public static DataSet Query(string SQLString, params SQLiteParameter[]
cmdParms)
{
using
(SQLiteConnection connection = new
SQLiteConnection(connectionString))
{
SQLiteCommand cmd = new SQLiteCommand();
PrepareCommand(cmd, connection, null, SQLString, cmdParms);
using (SQLiteDataAdapter da = new
SQLiteDataAdapter(cmd))
{
DataSet ds = new DataSet();
try
{
da.Fill(ds, "ds");
cmd.Parameters.Clear();
}
catch (System.Data.SQLite.SQLiteException
ex)
{
throw new Exception(ex.Message);
}
return ds;
}
}
}
public static void PrepareCommand(SQLiteCommand cmd, SQLiteConnection conn,
SQLiteTransaction trans, string cmdText, SQLiteParameter[]
cmdParms)
{
if (conn.State != ConnectionState.Open)
conn.Open();
cmd.Connection = conn;
cmd.CommandText = cmdText;
if (trans != null)
cmd.Transaction = trans;
cmd.CommandType = CommandType.Text;//cmdType;
if
(cmdParms !=
null)
{
foreach (SQLiteParameter parameter in
cmdParms)
{
if ((parameter.Direction == ParameterDirection.InputOutput
|| parameter.Direction == ParameterDirection.Input) &&
(parameter.Value ==
null))
{
parameter.Value = DBNull.Value;
}
cmd.Parameters.Add(parameter);
}
}
}
#endregion
#region 参数转换
///
<summary>
///
放回一个SQLiteParameter
///
</summary>
/// <param
name="name">参数名字</param>
/// <param
name="type">参数类型</param>
/// <param
name="size">参数大小</param>
/// <param
name="value">参数值</param>
///
<returns>SQLiteParameter的值</returns>
public static SQLiteParameter MakeSQLiteParameter(string name,
DbType type, int size, object
value)
{
SQLiteParameter parm = new SQLiteParameter(name, type, size);
parm.Value = value;
return parm;
}
public static SQLiteParameter
MakeSQLiteParameter(string name, DbType type, object
value)
{
SQLiteParameter parm = new SQLiteParameter(name, type);
parm.Value = value;
return parm;
}
#endregion
}
}