## v0.9.17 (ODBC)

- 增加 FreeSql.Provider.Odbc，实现 Oracle/SqlServer/MySql 的 Odbc 访问提供；
- 增加 FreeSqlBuilder.UseConnectionString 参数 providerType，可解决因包版本冲突时，可能无法反射获得 FreeSql.Provider 对应的类型，通常这个参数不需要设置；
- 优化 MaxLength 特性，当指定为 -1 时 DbType 会分别映射类型 text/nvarchar(max)/nvarchar2(4000)；

Providers/FreeSql.Provider.Odbc/Oracle/Curd/OdbcOracleUpdate.cs

@@ -0,0 +1,72 @@
+using FreeSql.Internal;
+using FreeSql.Internal.Model;
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace FreeSql.Odbc.Oracle
+{
+
+    class OdbcOracleUpdate<T1> : Internal.CommonProvider.UpdateProvider<T1> where T1 : class
+    {
+
+        public OdbcOracleUpdate(IFreeSql orm, CommonUtils commonUtils, CommonExpression commonExpression, object dywhere)
+            : base(orm, commonUtils, commonExpression, dywhere)
+        {
+        }
+
+        public override int ExecuteAffrows() => base.SplitExecuteAffrows(200, 999);
+        public override Task<int> ExecuteAffrowsAsync() => base.SplitExecuteAffrowsAsync(200, 999);
+        public override List<T1> ExecuteUpdated() => base.SplitExecuteUpdated(200, 999);
+        public override Task<List<T1>> ExecuteUpdatedAsync() => base.SplitExecuteUpdatedAsync(200, 999);
+
+
+        protected override List<T1> RawExecuteUpdated()
+        {
+            throw new NotImplementedException();
+        }
+        protected override Task<List<T1>> RawExecuteUpdatedAsync()
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override void ToSqlCase(StringBuilder caseWhen, ColumnInfo[] primarys)
+        {
+            if (_table.Primarys.Length == 1)
+            {
+                caseWhen.Append(_commonUtils.QuoteReadColumn(_table.Primarys.First().Attribute.MapType, _commonUtils.QuoteSqlName(_table.Primarys.First().Attribute.Name)));
+                return;
+            }
+            caseWhen.Append("(");
+            var pkidx = 0;
+            foreach (var pk in _table.Primarys)
+            {
+                if (pkidx > 0) caseWhen.Append(" || ");
+                caseWhen.Append(_commonUtils.QuoteReadColumn(pk.Attribute.MapType, _commonUtils.QuoteSqlName(pk.Attribute.Name)));
+                ++pkidx;
+            }
+            caseWhen.Append(")");
+        }
+
+        protected override void ToSqlWhen(StringBuilder sb, ColumnInfo[] primarys, object d)
+        {
+            if (_table.Primarys.Length == 1)
+            {
+                sb.Append(_commonUtils.FormatSql("{0}", _table.Primarys.First().GetMapValue(d)));
+                return;
+            }
+            sb.Append("(");
+            var pkidx = 0;
+            foreach (var pk in _table.Primarys)
+            {
+                if (pkidx > 0) sb.Append(" || ");
+                sb.Append(_commonUtils.FormatSql("{0}", pk.GetMapValue(d)));
+                ++pkidx;
+            }
+            sb.Append(")");
+        }
+    }
+}