知识大全 ado.net快速上手实践篇（二）

Posted 2022-07-17 知

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五 dal层数据访问实现 在这里我们使用前一篇文章里实现的数据持久化层和伪SqlMapper对象实现数据操作下面我们来看看Dal下核心的Dao如何实现还记得我们在下面的dao类是怎么实现的吗？没错我们根据一个基类BaseDAO和它的构造函数实现dao的配置加载但是楼猪的实现没有那么复杂和强大本文的实现其实就是通过BaseDAO和构造函数获取数据库连接对象的key 初始化一个SqlMapper 然后利用SqlMapper对象进行基本的CRUD等等数据操作那么我们如何利用BaseDAO和构造函数就像以前在系列文章里的提到的Dal层下那样进行SqlMapper的初始化呢？ 在AdoNetDataaccess Mapper下我们定义公共的BaseDAO类 代码 namespace AdoNetDataAccess Mapper public abstract class BaseDAO #region PRoperties public SqlMapper SqlMapper get; set; #endregion #region Constructor private BaseDAO() /// <summary> /// SqlMapper属性适用 /// </summary> /// <param name= mapperName ></param> public BaseDAO(string mapperName) this SqlMapper = MapperUtill GetMapper(mapperName); #endregion 初始化SqlMapper的实用类 代码 using System; using System Collections Generic; using System Configuration; namespace AdoNetDataAccess Mapper using AdoNetDataAccess Core Contract; using AdoNetDataAccess Core Implement; public sealed class MapperUtill #region fields public static string currentSqlKey = sqlConn ; public static int cmdTimeOut = ; private static readonly object objSync = new object(); private static readonly IDictionary<string SqlMapper> dictMappers = new Dictionary<string SqlMapper>(); #endregion #region constructor and methods private MapperUtill() static MapperUtill() try cmdTimeOut = int Parse(ConfigurationManager AppSettings[ db_timeOut ]); catch cmdTimeOut = ; //实例化SqlDbMapper for (int i = ; i < ConfigurationManager ConnectionStrings Count; i++) string key = ConfigurationManager ConnectionStrings[i] Name; string value = ConfigurationManager ConnectionStrings[i] ConnectionString; CreateMapper(key value cmdTimeOut); public static SqlMapper GetSqlMapper(string key) return MapperUtill GetMapper(key); public static SqlMapper GetCurrentSqlMapper() return MapperUtill GetMapper(currentSqlKey); public static void CreateMapper(string connKey string sqlConStr int connTimeOut) IDbOperation operation = new SqlServer(sqlConStr connTimeOut); SqlMapper mapper = new SqlMapper(operation); dictMappers Add(connKey ToUpper() Trim() mapper);//不区分大小写 public static SqlMapper GetMapper(string sqlConKey) if (string IsNullOrEmpty(sqlConKey)) throw new Exception( 数据库连接字符串主键为空! ); sqlConKey = sqlConKey ToUpper();//不区分大小写 SqlMapper mapper = null; if (dictMappers ContainsKey(sqlConKey)) mapper = dictMappers[sqlConKey]; else throw new Exception(string Format( 没有所对应的数据库连接 sqlConKey)); return mapper; /// <summary> /// 释放所有 /// </summary> public void Release() foreach (KeyValuePair<string SqlMapper> kv in dictMappers) SqlMapper mapper = kv Value; if (mapper == null) continue; mapper CurrentDbOperation CloseConnection(); dictMappers Clear(); #endregion 这个实用类的重要作用就是初始化配置文件里connectionStrings配置节点以获取sql连接对象必须的连接字符串 PersonDao类 下面就是针对具体的Person表的数据操作了代码 using System Collections Generic; using System Data; namespace AdoNetDataAccess Dal Dao using AdoNetDataAccess Dal Model; using AdoNetDataAccess Dal Utility; using AdoNetDataAccess Mapper; public class PersonDao : BaseDAO public PersonDao() : base( sqlConn )//sqlConn是<connectionStrings>配置节点的一个name public int Insert(string sqlInsert) int id = this SqlMapper Insert(sqlInsert); //object obj = this SqlMapper ExecuteScalar(sqlInsert System Data CommandType Text null); return id; public bool BatchInsert(IList<Person> listModels) int batchSize = ; int copyTimeOut = ; DataTable dt = DataTableHelper CreateTable<Person>(listModels); bool flag = this SqlMapper BatchInsert(typeof(Person) Name batchSize copyTimeOut dt); return flag; public int Update(string sqlUpdate) int result = this SqlMapper Update(sqlUpdate); return result; public IList<Person> SelectPersons(string sqlSelect) IList<Person> listPersons = this SqlMapper QueryForList<Person>(sqlSelect); return listPersons; public IDictionary<int Person> SelectDictPersons(string sqlSelect) IDictionary<int Person> dictPersons = this SqlMapper QueryForDictionary<int Person>( Id sqlSelect); return dictPersons; public DataTable SelectPersonTable(string sqlSelect) DataTable dt = this SqlMapper FillDataTable(sqlSelect CommandType Text null); return dt; public DataSet SelectPersonDataSet(string sqlSelect) DataSet ds = this SqlMapper FillDataSet(sqlSelect CommandType Text null); return ds; public int Delete(string sqlDelete) int result = this SqlMapper Delete(sqlDelete); return result; 到这里一个dao类操作就实现了然后我们按步就班实现对外调用的服务接口在表现层调用吧 六表现层的调用 配置文件 代码 <appSettings> <add key= db_timeOut value= /> </appSettings> <connectionStrings> <add name= sqlConn connectionString= Data Source= \\sqlexpress; Initial Catalog=TestDb; User Id=sa; PassWord= ; /> <add name= sqlConnStr connectionString= Data Source= \\sqlexpress; Initial Catalog=TestDb; User Id=sa; Password= ; /> <add name= sqlConnStr connectionString= Data Source= \\sqlexpress; Initial Catalog=TestDb; User Id=sa; Password= ; /> </connectionStrings> 其中 connectionString是必须的如果没有我们无法加载调用可用的SqlMapper CRUD操作测试 代码 using System; using System Collections; using System Collections Generic; using System Data; namespace OOXXWebApp using AdoNetDataAccess Dal; using AdoNetDataAccess Dal Model; public partial class _Default : System Web UI Page protected void Page_Load(object sender EventArgs e) if (!IsPostBack) //增删改查测试 string sqlInsert = INSERT Person (FirstName LastName Weight Height) VALUES( jeff wong ) SELECT @@IDENTITY FROM Person(NOLOCK) ; string sqlUpdate = UPDATE Person SET Height= WHERE Id= ; string sqlSelect = SELECT TOP * FROM Person(NOLOCK) ; string sqlDelete = DELETE Person WHERE Id> AND Id< ; IList<Person> listModels = new List<Person>(); for (int i = ; i < ; i++) Person model = new Person(); model FirstName = Jeff ; model LastName = Wong ; model Weight = ; model Height = ; listModels Add(model); Response Write( Test Beginning ); int id = ServiceFactory CreatePersonService() Add(sqlInsert); Response Write(string Format( Insert and return id: id)); bool flag = ServiceFactory CreatePersonService() BatchInsert(listModels); Response Write(string Format( Batch Insert flag ? succeed : failed )); IList<Person> listPersons = ServiceFactory CreatePersonService() GetPersons(sqlSelect); Response Write(string Format( Select pesons and return persons: listPersons Count)); IDictionary<int Person> dictPersons = ServiceFactory CreatePersonService() GetDictPersons(sqlSelect); Response Write(string Format( Select pesons and return dictionary persons: dictPersons Count)); DataTable dt = ServiceFactory CreatePersonService() GetPersonTable(sqlSelect); Response Write(string Format( Select pesons and return persons: dt Rows Count)); DataSet ds = ServiceFactory CreatePersonService() GetPersonDataSet(sqlSelect); Response Write(string Format( Select pesons and return persons: ds Tables[ ] Rows Count)); int affectNum = ServiceFactory CreatePersonService() Modify(sqlUpdate); Response Write(string Format( Update and affect rows : affectNum)); affectNum = ; affectNum = ServiceFactory CreatePersonService() Remove(sqlDelete); Response Write(string Format( Delete and affect rows : affectNum)); Response Write( Test End ); 这个就不用多说了吧表现层写SQL语句调用写好的服务就行了比较不舒服的地方就是SQL语句不得不写在类里面如果自动生成或者独立放在xml下实现可配置的形式那就更好了当然sql语句不是我们讨论的重点您有好的方法可以自己扩展实现更人性化的功能减少书写SQLl语句的工作 七最后对demo工程文件结构进行简单说明 数据持久化层AdoNetDataAccess Core SqlMapper层AdoNetDataAccess Mapper（引用AdoNetDataAccess Core）具体数据操作使用层AdoNetDataAccess Dal（引用AdoNetDataAccess Mapper）表现层AdoNetDataAccessWebApp（引用AdoNetDataAccess Dal）可以看出工程里的文件结构还是很清晰的需要学习的童鞋不妨下载使用试试看吧 cha138/Article/program/net/201311/11765