clr - Oracle Data Provider 到 CLR 类型映射

Question

在哪里可以找到 ODP 到 CLR 类型映射的列表？在 Oracle 数据库上，NUMBER(9,0) 类型在 .NET 应用程序中作为 MS Oracle 驱动程序的 System.Decimal 出现，但作为 System.Int32 来自 ODP 驱动程序。我需要来自数据库的类型的确切规范(不是 CLR 到数据库参数映射)。

Answer 1

运行此简单测试以获取 SqlServer 和 Oracle(MS 和 ODP.NET 驱动程序)的映射:

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using Oracle.DataAccess.Client;

namespace DbOutTypeTest
{
    public class Program
    {
        private static string SqlServerConnectionString = @"";
        private static string OracleConnectionString = @"";

        private static void WriteHeader(string title)
        {
            Console.WriteLine("----------------------------------------------------------");
            Console.WriteLine("-- {0}", title);
            Console.WriteLine("----------------------------------------------------------");
        }

        private static void WriteRow(string key, string value)
        {
            Console.WriteLine("{0}\t\t{1}", key.PadRight(30, ' '), value);
        }

        private static void EnumerateTypes(IDbConnection connection, string template, IEnumerable<string> types)
        {
            EnumerateTypes(connection, template, types, (arg1, arg2) => { });
        }

        private static void EnumerateTypes(IDbConnection connection, string template, IEnumerable<string> types, Action<string, string> action)
        {
            connection.Open();
            using (var command = connection.CreateCommand())
            {
                foreach (var type in types)
                {
                    var value = "";
                    command.CommandText = string.Format(template, type);
                    try
                    {
                        using (var reader = command.ExecuteReader())
                        {
                            if (reader.Read())
                                value = reader[0].GetType().FullName;
                            else
                                value = "<no data read>";
                        }
                    }
                    catch (Exception ex)
                    {
                        value = ex.Message;
                    }
                    WriteRow(type, value);
                    action(type, value);
                }
            }
        }

        private static IEnumerable<string> SqlServerIntegers()
        {
            yield return "tinyint";
            yield return "smallint";
            yield return "int";
            yield return "bigint";
            for (int precision = 1; precision <= 38; ++precision)
            {
                yield return "numeric(" + precision + ", 0)";
            }
            yield break;
        }

        private static IEnumerable<string> SqlServerFloatings()
        {
            yield return "real";
            yield return "float";
            for (int precision = 1; precision <= 38; ++precision)
            {
                for (int scale = 1; scale <= precision; ++scale)
                    yield return "numeric(" + precision + ", " + scale + ")";
            }
            yield break;
        }

        private static IEnumerable<string> OracleIntegers()
        {
            for (int precision = 1; precision <= 38; ++precision)
            {
                yield return "number(" + precision + ", 0)";
            }
            yield break;
        }

        private static IEnumerable<string> OracleFloatings()
        {
            for (int precision = 1; precision <= 38; ++precision)
            {
                for (int scale = 1; scale <= precision; ++scale)
                    yield return "number(" + precision + ", " + scale + ")";
            }
            yield break;
        }

        public static void Main(string[] args)
        {
            WriteHeader("C# types - CLR names");
            Console.WriteLine("{0}\t\t{1}",   "byte".PadRight(30, ' '), typeof(byte).FullName);
            Console.WriteLine("{0}\t\t{1}",  "short".PadRight(30, ' '), typeof(short).FullName);
            Console.WriteLine("{0}\t\t{1}",    "int".PadRight(30, ' '), typeof(int).FullName);
            Console.WriteLine("{0}\t\t{1}",   "long".PadRight(30, ' '), typeof(long).FullName);
            Console.WriteLine("{0}\t\t{1}",  "float".PadRight(30, ' '), typeof(float).FullName);
            Console.WriteLine("{0}\t\t{1}", "double".PadRight(30, ' '), typeof(double).FullName);

            var OracleToClrInteger = new Dictionary<string, string>();
            var OracleToClrFloating = new Dictionary<string, string>();
            var SqlServerToClrInteger = new Dictionary<string, string>();
            var SqlServerToClrFloating = new Dictionary<string, string>();

            WriteHeader("Oracle integers mapping (Oracle Data Provider)");
            using (var connection = new OracleConnection(OracleConnectionString))
            {
                EnumerateTypes(connection, "SELECT CAST(0 AS {0}) FROM DUAL", OracleIntegers(), (type, value) => OracleToClrInteger.Add(type, value));
            }

            WriteHeader("SQLServer integers mapping");
            using (var connection = new SqlConnection(SqlServerConnectionString))
            {
                EnumerateTypes(connection, "SELECT CAST(0 AS {0})", SqlServerIntegers(), (type, value) => SqlServerToClrInteger.Add(type, value));
            }

            WriteHeader("Oracle integers mapping (Microsoft Oracle Client)");
            using (var connection = new System.Data.OracleClient.OracleConnection(OracleConnectionString))
            {
                EnumerateTypes(connection, "SELECT CAST(0 AS {0}) FROM DUAL", OracleIntegers());
            } 

            WriteHeader("Oracle floats mapping (Oracle Data Provider)");
            using (var connection = new OracleConnection(OracleConnectionString))
            {
                EnumerateTypes(connection, "SELECT CAST(0 AS {0}) FROM DUAL", OracleFloatings(), (type, value) => OracleToClrFloating.Add(type, value));
            }

            WriteHeader("SQLServer floats mapping");
            using (var connection = new SqlConnection(SqlServerConnectionString))
            {
                EnumerateTypes(connection, "SELECT CAST(0 AS {0})", SqlServerFloatings(), (type, value) => SqlServerToClrFloating.Add(type, value));
            }

            WriteHeader("Oracle floats mapping (Microsoft Oracle Client)");
            using (var connection = new System.Data.OracleClient.OracleConnection(OracleConnectionString))
            {
                EnumerateTypes(connection, "SELECT CAST(0 AS {0}) FROM DUAL", OracleFloatings());
            }

            WriteHeader("Suggested integer type mapping Oracle -> SqlServer");
            foreach (var pair in OracleToClrInteger)
            {
                if (pair.Value == "System.Decimal")
                    WriteRow(pair.Key, pair.Key.Replace("number", "numeric"));
                else
                {
                    if (!SqlServerToClrInteger.Values.Contains(pair.Value))
                        WriteRow(pair.Key, "???");
                    else
                        WriteRow(pair.Key, SqlServerToClrInteger.First(p => p.Value == pair.Value).Key);
                }
            }

            WriteHeader("Suggested floating type mapping Oracle -> SqlServer");
            foreach (var pair in OracleToClrFloating)
            {
                if (pair.Value == "System.Decimal")
                    WriteRow(pair.Key, pair.Key.Replace("number", "numeric"));
                else
                {
                    if (!SqlServerToClrFloating.Values.Contains(pair.Value))
                        WriteRow(pair.Key, "???");
                    else
                        WriteRow(pair.Key, SqlServerToClrFloating.First(p => p.Value == pair.Value).Key);
                }
            }

        }
    }
}

最有趣的部分:

----------------------------------------------------------
-- Oracle integers mapping (Oracle Data Provider)
----------------------------------------------------------
number(1, 0)                        System.Int16
number(2, 0)                        System.Int16
number(3, 0)                        System.Int16
number(4, 0)                        System.Int16
number(5, 0)                        System.Int32
number(6, 0)                        System.Int32
number(7, 0)                        System.Int32
number(8, 0)                        System.Int32
number(9, 0)                        System.Int32
number(10, 0)                       System.Int64
number(11, 0)                       System.Int64
number(12, 0)                       System.Int64
number(13, 0)                       System.Int64
number(14, 0)                       System.Int64
number(15, 0)                       System.Int64
number(16, 0)                       System.Int64
number(17, 0)                       System.Int64
number(18, 0)                       System.Int64
number(19, 0)                       System.Decimal
number(20, 0)                       System.Decimal
number(21, 0)                       System.Decimal
number(22, 0)                       System.Decimal
number(23, 0)                       System.Decimal
number(24, 0)                       System.Decimal