Firebird Fluentdata

Fluentdata 支持很多种数据库驱动，但对Firebird不友好，不过可以使用DB2Provider来操作大部分功能，

例如： new DbContext().ConnectionString(connectionString, new DB2Provider(), FirebirdClientFactory.Instance)

但是对于Insert后获取自动生成的最大Id，就会报错，因为DB2的语法不通。

起初怀疑获取最大Id方法是通过自动添加select max(id)来获取，这样就有可能访问量大时会存在错误。

好在官网有源码可以查看，结果不是的。

每种数据库都有insert后获取inserted记录的Id的方法，Firebird也不例外，语法是： insert A (x,x) values (x,x) returning id, x, x 和Oracle语法差不多。

那就果断添加一个 FirebirdProvider ，后续我们再查看下其他各数据库ExecuteReturnLastId的具体做法。

FirebirdProvider 代码：

 using System;
 using System.Collections.Generic;
 using System.Data;
 using System.Linq;
 using System.Text;
 using FluentData.Providers.Common;
 using FluentData.Providers.Common.Builders;

 namespace FluentData
 {
     public class FirebirdProvider: IDbProvider
     {
         public string ProviderName
         {
             get
             {
                 return "FirebirdSql.Data.FirebirdClient";
             }
         }

         public bool SupportsOutputParameters
         {
             get { return true; }
         }

         public bool SupportsMultipleResultsets
         {
             get { return true; }
         }

         public bool SupportsMultipleQueries
         {
             get { return true; }
         }

         public bool SupportsStoredProcedures
         {
             get { return true; }
         }

         public bool RequiresIdentityColumn
         {
             get { return false; }
         }

         public IDbConnection CreateConnection(string connectionString)
         {
             return ConnectionFactory.CreateConnection(ProviderName, connectionString);
         }

         public string GetParameterName(string parameterName)
         {
             return "@" + parameterName;
         }

         public string GetSelectBuilderAlias(string name, string alias)
         {
             return name + " as " + alias;
         }

         public string GetSqlForSelectBuilder(SelectBuilderData data)
         {
             var sql = "";
             sql = "select " + data.Select;
             sql += " from " + data.From;
             if (data.WhereSql.Length > )
                 sql += " where " + data.WhereSql;
             if (data.GroupBy.Length > )
                 sql += " group by " + data.GroupBy;
             if (data.Having.Length > )
                 sql += " having " + data.Having;
             if (data.OrderBy.Length > )
                 sql += " order by " + data.OrderBy;
             if (data.PagingItemsPerPage >
                 && data.PagingCurrentPage > )
             {
                 sql += string.Format(" rows {0} to {1}", data.GetFromItems(), data.GetToItems());
             }

             return sql;
         }

         public string GetSqlForInsertBuilder(BuilderData data)
         {
             return new InsertBuilderSqlGenerator().GenerateSql(this, "@", data);
         }

         public string GetSqlForUpdateBuilder(BuilderData data)
         {
             return new UpdateBuilderSqlGenerator().GenerateSql(this, "@", data);
         }

         public string GetSqlForDeleteBuilder(BuilderData data)
         {
             return new DeleteBuilderSqlGenerator().GenerateSql(this, "@", data);
         }

         public string GetSqlForStoredProcedureBuilder(BuilderData data)
         {
             return data.ObjectName;
         }

         public DataTypes GetDbTypeForClrType(Type clrType)
         {
             return new DbTypeMapper().GetDbTypeForClrType(clrType);
         }

         public object ExecuteReturnLastId<T>(IDbCommand command, string identityColumnName = null)
         {
             if (identityColumnName == null) identityColumnName = "id";

             string temp = command.Data.Sql.ToString().Trim();
             if (temp.EndsWith(";"))
                 command.Data.Sql.Clear().Append(temp.Substring(, temp.Length - ));

             command.ParameterOut("FluentDataLastId", command.Data.Context.Data.FluentDataProvider.GetDbTypeForClrType(typeof(T)));
             command.Sql(" returning " + identityColumnName);

             object lastId = null;

             command.Data.ExecuteQueryHandler.ExecuteQuery(false, () =>
             {
                 command.Data.InnerCommand.ExecuteNonQuery();

                 lastId = command.ParameterValue<object>("FluentDataLastId");
             });

             return lastId;
         }

         public void OnCommandExecuting(IDbCommand command)
         {
         }

         public string EscapeColumnName(string name)
         {
             return name;
         }
     }
 }

具体调用方法： new DbContext().ConnectionString(connectionString, new FirebirdProvider(), FirebirdClientFactory.Instance)

DB2做法是： select IDENTITY_VAL_LOCAL() as LastId from sysibm.sysdummy1;

Mysql做法是： select LAST_INSERT_ID() as `LastInsertedId`

Oracle做法是：sql结尾添加输出参数   returning id into :FluentDataLastId

PgSql做法是： select lastval();

Sqlite做法是： select last_insert_rowid();

SqlCe做法是： select cast(@@identity as int)

SqlServer做法是： select SCOPE_IDENTITY()

===================================================

实体方法扩展：

     public class Base
     {
         public long id { get; set; }
     }

     public class T_session : Base
     {
         public string token { get; set; }
         public long? user_id { get; set; }
         public DateTime login_time { get; set; }
         public DateTime? logout_time { get; set; }
         public DateTime update_time { get; set; }
     }

     public static class DbExt
     {
         public static long Insert(this Base enty, IDbContext db)
         {
             return db.Insert(enty.GetType().Name, enty).AutoMap(x => x.id).ExecuteReturnLastId<long>();
         }

         public static int Update(this Base enty, IDbContext db)
         {
             return db.Update(enty.GetType().Name, enty).AutoMap(x => x.id).Where(x => x.id).Execute();
         }

         public static int Delete(this Base enty, IDbContext db)
         {
             return db.Delete(enty.GetType().Name, enty).Where(x => x.id).Execute();
         }

     }