剖判sql中获得刚刚插入的数码的id

SELECT LAST_INSERT_ID()。SELECT
@@IDENTITY接可。但到深夜那兄弟还没化解。因为不精晓怎么运作。。项目都是三层的。基本是写在DBHELPERAV4中。原因是其写入了:

    // 省略建表  

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SQL插入数据时重临最新ID方法

    stmt.executeUpdate(“DROP TABLE IF EXISTS autoIncTutorial”);  

这就该选拔LAST_INSERT_ID了,因为LAST_INSERT_ID是依照Connection的,只要每一个线程都选取独立的
Connection对象,LAST_INSERT_ID函数将重临该Connection对AUTO_INCREMENT列最新的insert
or
update*作生成的首先个record的ID。这一个值不可能被此外客户端(Connection)影响,保险了你能够找回本人的
ID
而不用惦记其它客户端的位移,而且不须求加锁。使用单INSERT语句插入多条记下, 
LAST_INSERT_ID再次回到三个列表。

 

SELECT
LAST_INSERT_ID()。SELECT
@@IDENTITY接可。但到早上那兄弟还没化解。因为不通晓怎么运营。。项目都以三层的。…

            “INSERT INTO autoIncTutorial (dataField) ”  

可以用 SELECT last_insert_id();查询LAST_INSERT_ID的值.
Important: If you insert multiple rows using a single INSERT statement,
LAST_INSERT_ID() returns the value generated for the first inserted
row only.
应用单INSERT语句插入多条记下, 
LAST_INSERT_ID只回去插入的首先条记下发生的值. 比方

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

 

    rs = null;  

LAST_INSERT_ID: LAST_INSERT_ID
是与table非亲非故的,借使向表a插入数据后,再向表b插入数据,LAST_INSERT_ID会改变。
在多用户交替插入数据的状态下max(id)显著无法用。

注意事项

cmd.ExecuteScalar();
回来首行首列。也许是因为helper里面注释为:

    if (rs.next()) {  

 mysql> INSERT INTO t VALUES (NULL, ‘aaaa’), (NULL, ‘bbbb’), (NULL,
‘cccc’);  
 mysql> SELECT * FROM t;  
 +—-+——+  
 | id | name |  
 +—-+——+  
 |  1 | Bob  |  
 |  2 | aaaa |  
 |  3 | bbbb |  
 |  4 | cccc |  
 +—-+——+  
 mysql> SELECT LAST_INSERT_ID();  
 +——————+  
 | LAST_INSERT_ID() |  
 +——————+  
 |                2 |  
 +——————+ 
ID 2 是在插入第一条记录aaaa 时爆发的.
select @@IDENTITY:
String sql=”select @@IDENTITY”;
@@identity是意味的是近年来一遍向装有identity属性(即自增列)的表插入数据时对应的自增列的值,是系统定义的全局变量。一般系统
定义的全局变量都以以@@初叶,用户自定义变量以@发轫。比方有个表A,它的自增列是id,当向A表插入一行数据后,假诺插入数据后自增列的值自动扩大至
101,则透过select
@@identity获得的值正是101。动用@@identity的前提是在张开insert操作后,推行select
@@identity的时候总是未有小憩,不然获得的将是NULL值。

/// <summary> /// 剖断用户是或不是留存 /// </summary> ///
<param name=”name”>用户名称</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> /// 扩展贰个用户 /// </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> ///
更新一条数据 /// </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()); }

cmd.ExecuteNonQuery(); —那是推行非查询语句重临受影响的行数。
骨子里是相应写入:

    int autoIncKeyFromFunc = -1;  

/**************************************
* 功效:SQLLite Server操作完毕
**************************************/
using System; using System.Collections; using
System.Collections.Specialized; using System.Data; using
System.Data.SQLite;//那么些能够去网络下载 using System.Configuration;
public class SQLiteHelper {
//数据库连接字符串(web.config来配置),能够动态改造SQLString补助大多据库.
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
Get马克斯ID(string 菲尔德Name, 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
实践简单SQL语句 /// <summary> /// 施行SQL语句,重返影响的记录数
/// </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> ///
实践SQL语句,设置命令的进行等待时间 /// </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> ///
实践多条SQL语句,达成数据库事务。 /// </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> ///
试行带三个仓储进程参数的的SQL语句。 /// </summary> /// <param
name=”SQLString”>SQL语句</param> /// <param
name=”content”>参数内容,举例多个字段是格式复杂的篇章,有特殊符号,能够透过那一个点子加多</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>
/// 试行带贰个仓库储存进度参数的的SQL语句。 /// </summary> ///
<param name=”SQLString”>SQL语句</param> /// <param
name=”content”>参数内容,比方八个字段是格式复杂的篇章,有特殊符号,能够透过这几个艺术加多</param>
/// <returns>影响的笔录数</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Curry插入图像格式的字段(和地方情状好像的另一种实例) ///
</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的气象</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> ///
试行一条计算查询结果语句,重临查询结果(object)。 /// </summary>
/// <param name=”SQLString”>总结查询结果语句</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> ///
试行查询语句,重临SQLiteData里德r(使用该措施切记要手工业关闭SQLiteDataReader和三番两次)
/// </summary> /// <param
name=”strSQL”>查询语句</param> ///
<returns>SQLiteData里德r</returns> public static
SQLiteDataReader ExecuteReader(string strSQL) { SQLiteConnection
connection = new SQLiteConnection(connectionString); SQLiteCommand cmd =
new SQLiteCommand(strSQL, connection); try { connection.Open();
SQLiteData里德r myReader = cmd.ExecuteReader(); return myReader; }
catch (System.Data.SQLite.SQLiteException e) { throw new
Exception(e.Message); } //finally
//无法在此关闭,不然,再次来到的对象将无法利用 //{ // cmd.Dispose(); //
connection.Close(); //} } /// <summary> ///
试行查询语句,重临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> ///
施行查询语句,重临DataSet,设置命令的施行等待时间 /// </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
试行带参数的SQL语句 /// <summary> ///
推行SQL语句,重返影响的笔录数 /// </summary> /// <param
name=”SQLString”>SQL语句</param> ///
<returns>影响的笔录数</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> /// 推行多条SQL语句,完成数据库事务。 ///
</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> ///
实践一条总结查询结果语句,重返查询结果(object)。 /// </summary>
/// <param name=”SQLString”>总计查询结果语句</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> ///
奉行查询语句,重临SQLiteDataReader
(使用该格局切记要手工业关闭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 //不可能在此关闭,否则,重返的目的将无法使用 //{ //
cmd.Dispose(); // connection.Close(); //} } /// <summary> ///
实践查询语句,重临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 参数转变 ///
<summary> /// 放回二个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 }

LAST_INSERT_ID() mysql教程_insert_id
获取insert数据的主键值自动编号那么来剖析一下它们的界别吗
 mysql_insert_id
()是直接获取当前session的insert_id,而LAST_INSERT_ID()是SQL函数,必要经过施行SQL来获得,如:SELECT
LAST_INSERT_ID();分明那七个功效是一模一样的,但实施壹回SQL要费用数不尽财富,不比直接通过mysql_insert_id()获得内部存款和储蓄器中的值快得多

    rs = stmt.getGeneratedKeys();                                  //
获取自增主键!  

  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,要是在作业中插入数据战败,并不会侵吞拉长后的id,而sql
    server中对应的id将对事情没有什么帮助
    6.
    SQLite中绝非GETDATE日期函数,在类中投入参数如下DbType.DateTime,DateTime.Now.ToString(“s”)
  6. SQLite支持REPLACE INTO语法,sql server 2008中支持merge to

     /// <summary>
        /// 实践一条总计查询结果语句,重返查询结果(object)。
        /// </summary>
        /// <param
name=”SQLString”>计算查询结果语句</param>
        /// <returns>查询结果(object)</returns>

    stmt = conn.createStatement();  

 

            Statement.RETURN_GENERATED_KEYS);                      //
向驱动指明需求活动得到generatedKeys!  

 

这种方法只需求2个步骤:1. 在executeUpdate时激活自动得到key;
2.调用Statement的getGeneratedKeys()接口

 调用艺术

    stmt.executeUpdate(                                              
 // 创建demo表  

ResultSet rs = null;  

    }   

    System.out.println(“Key returned for inserted row: ”  

    // …  

 

    rs.last();                                                        
// 移动游标到最后一行  

INSERT INTO t VALUES  

通过SQL select LAST_INSERT_ID()函数

    rs.insertRow();                                                  
 // 插入记录  

}  finally { … }  

  1. 通过JDBC2.0提供的insertRow()方式

    stmt.executeUpdate(  

ResultSet rs = null;  

        // throw an exception from here  

LAST_INSERT_ID(),
@@IDENTITY都只会回来’Mary’所在的那条记下的generatedKey

    // …  

这种格局没什么好说的,正是外加查询三遍函数LAST_INSERT_ID().

  1. 操作方便,代码简洁

  2. jdbc3.0的标准

  3. 频率高,因为未有额外访问数据库

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