sqliteSQLite数据库操作类

首先:添加配置<add key=”SQLString” value=”~\demo.db”/>

 

/**************************************
* 作用:SQLLite Server操作实现
**************************************/
using System; using System.Collections; using
System.Collections.Specialized; using System.Data; using
System.Data.SQLite;//这个可去网上下载 using System.Configuration;
public class SQLiteHelper {
//数据库连接字符串(web.config来布局),可以动态更改SQLString支持多数仍库.
public static string connectionString = “Data Source=” +
System.Web.HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings[“SQLString”]);
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,返回影响之笔录数
/// </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,设置命令的推行等时 /// </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> ///
执行多漫长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> ///
执行带来一个囤过程参数的之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篇章,有特殊符号,可以透过者办法添加</param>
/// <returns>影响的笔录数</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>
/// 执行带来一个囤过程参数的的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章,有特殊符号,可以透过这个主意添加</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> ///
向数据库里安插图像格式的字段(和点情况好像之另外一样种植实例) ///
</summary> /// <param name=”strSQL”>SQL语句</param>
/// <param
name=”fs”>图像字节,数据库的字段类型也image的情事</param> ///
<returns>影响之笔录数</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> ///
执行同样长条计查询结果语句,返回查询结果(object)。 /// </summary>
/// <param name=”SQLString”>计算查询结果告知句</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)
/// </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
//不克以这个关闭,否则,返回的靶子将无法用 //{ // 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,设置命令的尽等时 /// </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
执行带来参数的SQL语句 /// <summary> ///
执行SQL语句,返回影响之记录数 /// </summary> /// <param
name=”SQLString”>SQL语句</param> ///
<returns>影响之笔录数</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> /// 执行多长达SQL语句,实现数据库事务。 ///
</summary> /// <param
name=”SQLStringList”>SQL语句之哈希表(key为sql语句,value是该语句之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> ///
执行同一修计查询结果语句,返回查询结果(object)。 /// </summary>
/// <param name=”SQLString”>计算查询结果报告句</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 //不克在此关闭,否则,返回的靶子将无法利用 //{ //
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 }

 调用艺术

/// <summary> /// 判断用户是否存在 /// </summary> ///
<param name=”name”>用户称</param> ///
<returns></returns> public bool UserExists(string name) {
StringBuilder strSql = new StringBuilder(); strSql.Append(“select
count(*) n from Users”); strSql.Append(” where UserName=@UserName “);
SQLiteParameter[] parameters = {
SQLiteHelper.MakeSQLiteParameter(“@UserName”, DbType.String,30,name)};
return SQLiteHelper.Exists(strSql.ToString(), parameters); } ///
<summary> /// 增加一个用户 /// </summary> /// <param
name=”name”>用户名</param> /// <param
name=”pwd”>密码</param> /// <returns></returns>
public int CreateUser(string name, string pwd) { int ret = 0; if
(!UserExists(name)) { StringBuilder strSql = new StringBuilder();
strSql.Append(“insert into t_UserGroup(“);
strSql.Append(“UserName,Password)”); strSql.Append(” values (“);
strSql.Append(“@UserName,@Password)”); SQLiteParameter[] parameters =
{ SQLiteHelper.MakeSQLiteParameter(“@UserName”, DbType.String,30,name),
SQLiteHelper.MakeSQLiteParameter(“@Password”, DbType.String,128,pwd) };
if (SQLiteHelper.ExecuteSql(strSql.ToString(), parameters) >= 1) {
ret = 1; } } else { ret = 2; } return ret; } /// <summary> ///
更新一修数据 /// </summary> /// <param
name=”model”>用户分组实体类</param> ///
<returns></returns> public bool UpdateUser(int id, string
name, string pwd) { StringBuilder strSql = new StringBuilder();
strSql.Append(“update Users set “);
strSql.Append(“UserName=@UserName,”);
strSql.Append(“Password=@Password”); strSql.Append(” where
UserID=@UserID”); SQLiteParameter[] parameters = {
SQLiteHelper.MakeSQLiteParameter(“@UserID”, DbType.Int32,11,id),
SQLiteHelper.MakeSQLiteParameter(“@UserName”, DbType.String,30,name),
SQLiteHelper.MakeSQLiteParameter(“@Password”, DbType.String,128,pwd)};
if (SQLiteHelper.ExecuteSql(strSql.ToString(), parameters) >= 1) {
return true; } else { return false; } } /// <summary> /// 删除用户
/// </summary> /// <param name=”ID”>用户ID</param> ///
<returns></returns> public int DeleteUser(int id) { int ret
= 0; string strSql3 = “delete from Users where UserID=@UserID”;
SQLiteParameter[] parameters = {
SQLiteHelper.MakeSQLiteParameter(“@UserID”, DbType.Int32,4,id)}; if
(SQLiteHelper.ExecuteSql(strSql3, parameters) >= 1) { ret = 1; } else
{ ret = 0; } return ret; } /// <summary> /// 获得用户分组数据列表
/// </summary> /// <param
name=”strWhere”>Where条件</param> ///
<returns></returns> public DataSet GetUserList(string
strWhere) { StringBuilder strSql = new StringBuilder();
strSql.Append(“select * FROM Users “); if (strWhere.Trim() != “”) {
strSql.Append(” where ” + strWhere); } strSql.Append(” order by UserID
desc”); return SQLiteHelper.Query(strSql.ToString()); }

 

 

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自添字段,如果以作业中插数据失败,并无会见占有增长后的id,而sql
    server中对应之id将无济于事
    6.
    SQLite中从来不GETDATE日期函数,在看似中加入参数如下DbType.DateTime,DateTime.Now.ToString(“s”)
  6. SQLite支持REPLACE INTO语法,sql server 2008中支持merge to

 

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