完美解決CodeSmith無法獲取MySQL表及列Description說明註釋的方案

weixin_34402090發表於2014-12-06

問題描述:

  CodeSmith是現在比較實用的程式碼生成器,但是我們發現一個問題:

  使用CodeSmith編寫MySQL模板的時候,會發現一個問題:MySQL資料表中的列說明獲取不到,也就是column.Description。如圖:

MySQL其中一張表,裡面每一列都設定有說明資訊

 

我們開啟CodeSmith編寫一個簡單的Model實體類的示例模板如下:

 1 <%-- 
 2 Name:           MySQL Model實體模板
 3 Author:         孤影[QQ:778078163]
 4 Description:    CodeSmith連線MySQL生成Model實體模板
 5 --%>
 6 
 7 <%@ Template Language="C#" TargetLanguage="C#" ResponseEncoding="UTF-8" %>
 8 
 9 <%@ Assembly Name="SchemaExplorer" %>
10 <%@ Import Namespace="SchemaExplorer" %>
11 
12 <%@ Property Name="SourceTable" Type="SchemaExplorer.TableSchema" Description="目標資料表" %>
13 <%@ Property Name="ModelNamespace" Type="System.String" Description="Model實體所在的名稱空間" %>
14 
15 using System;
16 using System.Collections.Generic;
17 using System.Linq;
18 using System.Text;
19 namespace <%=ModelNamespace %>
20 {
21     /// <summary>
22     /// <%=SourceTable.Description %>
23     /// </summary>
24     public class <%=SourceTable.Name %>
25     {
26         <%
27             // 迴圈遍歷 獲取當前資料表中的所有列
28             foreach(ColumnSchema column in SourceTable.Columns){
29                 Response.WriteLine(string.Format("// {0}",column.Description));
30                 Response.WriteLine(string.Format("public {0} {1} ;",GetCSharpVariableType(column),column.Name));
31             }
32         %>
33     }
34 }
35 
36 <script runat="template">
37 // 獲取指定列對應的C#資料型別
38 public string GetCSharpVariableType(ColumnSchema column)
39 {
40     if (column.Name.EndsWith("TypeCode")) return column.Name;
41     
42     switch (column.DataType)
43     {
44         case DbType.AnsiString: return "string";
45         case DbType.AnsiStringFixedLength: return "string";
46         case DbType.Binary: return "byte[]";
47         case DbType.Boolean: return "bool";
48         case DbType.Byte: return "byte";
49         case DbType.Currency: return "decimal";
50         case DbType.Date: return "DateTime";
51         case DbType.DateTime: return "DateTime";
52         case DbType.Decimal: return "decimal";
53         case DbType.Double: return "double";
54         case DbType.Guid: return "Guid";
55         case DbType.Int16: return "short";
56         case DbType.Int32: return "int";
57         case DbType.Int64: return "long";
58         case DbType.Object: return "object";
59         case DbType.SByte: return "sbyte";
60         case DbType.Single: return "float";
61         case DbType.String: return "string";
62         case DbType.StringFixedLength: return "string";
63         case DbType.Time: return "TimeSpan";
64         case DbType.UInt16: return "ushort";
65         case DbType.UInt32: return "uint";
66         case DbType.UInt64: return "ulong";
67         case DbType.VarNumeric: return "decimal";
68         default:
69         {
70             return "__UNKNOWN__" + column.NativeType;
71         }
72     }
73 }
74 </script>
一個簡單的CodeSmith生成Model實體的模板

 

然後我們點選生成,生成的程式碼如下圖:

表及每一列的說明都獲取失敗

 

當然,使用SQL Server及其他資料庫都是可以獲取到的,這是為什麼呢?

 

逼的沒招沒招了的時候,果斷開啟.NET Reflector,看看CodeSmith對SQL Server和MySQL二者,資料表生成操作的時候,有什麼不同的地方,或者有什麼缺少的地方。

CodeSmith中對MySQL操作的DLL元件位置是:“X:\...\CodeSmith\v7.0\SchemaProviders\SchemaExplorer.MySQLSchemaProvider.dll

 

展開後,開始一個個找裡面的方法,突然發現一個亮點:“GetTableColumns(string connectionString, TableSchema table);

這個字面的意思不就是獲取列資料麼?開啟看看。。。可惜,裡面只是根據表查詢所有列,並沒有Description相關操作。

 

繼續找,繼續對比。。。最終終於找到問題了:

方法“GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject);”裡面的查詢語句是:

string str = string.Format("SELECT EXTRA, COLUMN_DEFAULT, COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = '{0}' AND TABLE_NAME = '{1}' AND COLUMN_NAME = '{2}'", schema.Table.Database.Name, schema.Table.Name, schema.Name);

這個不就是獲取Column列中的擴充套件屬性的方法麼?!

對比發現,SQL Server的dll裡這個方法的下面,有返回Description,而MySQL正好沒有!

 

二話不說,找到CodeSmith的原始碼包解壓,翻出MySQL的專案:“X:\...\CodeSmith\v7.0\Samples\Samples\Projects\CSharp\MySQLSchemaProvider

然後開啟Visual Studio載入"MySQLSchemaProvider.csproj",有很多錯誤,那是因為缺少了引用,新增CodeSmith\bin裡面的相關引用即可。

 

 

需要引用的元件你可以在下面兩個CodeSmith安裝目錄中找到:

X:\...\CodeSmith\v7.0\bin\”、“X:\...\CodeSmith\v7.0\AddIns\

 

新增引用之後,錯誤就全部沒了:

 

然後我們果斷開始修改程式碼、首先找到剛剛那個獲取列擴充套件屬性的方法:

public ExtendedProperty[] GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject)

 

然後我們根據觀察SQL Server的程式碼,發現MySQL裡面這個方法:

在SQL語句查詢的時候少查詢了一項資料:“COLUMN_COMMENT”,於是我們首先修改它查詢的SQL語句如下:

string commandText = string.Format(@"SELECT EXTRA, COLUMN_DEFAULT, COLUMN_TYPE, COLUMN_COMMENT
                                                      FROM INFORMATION_SCHEMA.COLUMNS
                                                      WHERE TABLE_SCHEMA = '{0}' AND TABLE_NAME = '{1}' AND COLUMN_NAME = '{2}'",
                                                      columnSchema.Table.Database.Name, columnSchema.Table.Name, columnSchema.Name);

 

既然上面查詢了,按照正常的資料查詢流程,下面應該遍歷讀取,然後返回吧?

於是繼續看,下面有一個while,正是將上面查詢出來的資料返回的,我們對比SQL Server的程式碼發現:

上面查詢出來的每一項,下面都有獲取返回,而我們剛剛新增的那個“COLUMN_COMMENT”則沒有進行資料獲取、沒有怎麼辦?加唄~

獲取每個資料後,最後統一將封裝在“extendedProperties”中,於是我們也將獲取到的Description新增進去,其與步驟省略。最終修改的程式碼如下:

 1 public ExtendedProperty[] GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject)
 2         {
 3             List<ExtendedProperty> extendedProperties = new List<ExtendedProperty>();
 4 
 5             if (schemaObject is ColumnSchema)
 6             {
 7                 ColumnSchema columnSchema = schemaObject as ColumnSchema;
 8 
 9                 string commandText = string.Format(@"SELECT EXTRA, COLUMN_DEFAULT, COLUMN_TYPE, COLUMN_COMMENT
10                                                       FROM INFORMATION_SCHEMA.COLUMNS
11                                                       WHERE TABLE_SCHEMA = '{0}' AND TABLE_NAME = '{1}' AND COLUMN_NAME = '{2}'",
12                                                       columnSchema.Table.Database.Name, columnSchema.Table.Name, columnSchema.Name);
13 
14                 using (DbConnection connection = CreateConnection(connectionString))
15                 {
16                     connection.Open();
17 
18                     DbCommand command = connection.CreateCommand();
19                     command.CommandText = commandText;
20                     command.Connection = connection;
21 
22                     using (IDataReader reader = command.ExecuteReader(CommandBehavior.CloseConnection))
23                     {
24                         while (reader.Read())
25                         {
26                             string extra = reader.GetString(0).ToLower();
27                             bool columndefaultisnull = reader.IsDBNull(1);
28                             string columndefault = "";
29                             if (!columndefaultisnull)
30                             {
31                                 columndefault = reader.GetString(1).ToUpper();
32                             }
33                             string columntype = reader.GetString(2).ToUpper();
34                             string columncomment = reader.GetString(3);
35 
36                             bool isIdentity = (extra.IndexOf("auto_increment") > -1);
37                             extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.IsIdentity, isIdentity, columnSchema.DataType));
38 
39                             if (isIdentity)
40                             {
41                                 /*
42                                 MySQL auto_increment doesn't work exactly like SQL Server's IDENTITY
43                                 I believe that auto_increment is equivalent to IDENTITY(1, 1)
44                                 However, auto_increment behaves differently from IDENTITY when used
45                                 with multi-column primary keys.  See the MySQL Reference Manual for details.
46                                 */
47                                 extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.IdentitySeed, 1, columnSchema.DataType));
48                                 extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.IdentityIncrement, 1, columnSchema.DataType));
49                             }
50 
51                             extendedProperties.Add(new ExtendedProperty("CS_ColumnDefaultIsNull", columndefaultisnull, DbType.Boolean)); // Added for Backwards Compatibility.
52                             extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.DefaultValue, columndefault, DbType.String));
53                             extendedProperties.Add(new ExtendedProperty("CS_ColumnDefault", columndefault, DbType.String)); // Added for Backwards Compatibility.
54                             extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.SystemType, columntype, DbType.String));
55                             extendedProperties.Add(new ExtendedProperty("CS_ColumnType", columntype, DbType.String)); // Added for Backwards Compatibility.
56                             extendedProperties.Add(new ExtendedProperty("CS_ColumnExtra", extra.ToUpper(), DbType.String));
57                             extendedProperties.Add(new ExtendedProperty("CS_Description", columncomment, DbType.String));
58                         }
59 
60                         if (!reader.IsClosed)
61                             reader.Close();
62                     }
63 
64                     if (connection.State != ConnectionState.Closed)
65                         connection.Close();
66                 }
67             }
68             if (schemaObject is TableSchema)
69             {
70                 TableSchema tableSchema = schemaObject as TableSchema;
71                 string commandText = string.Format(@"SHOW CREATE TABLE `{0}`.`{1}`", tableSchema.Database.Name, tableSchema.Name);
72 
73                 using (DbConnection connection = CreateConnection(connectionString))
74                 {
75                     connection.Open();
76 
77                     DbCommand command = connection.CreateCommand();
78                     command.CommandText = commandText;
79                     command.Connection = connection;
80 
81                     using (IDataReader reader = command.ExecuteReader(CommandBehavior.CloseConnection))
82                     {
83                         while (reader.Read())
84                         {
85                             string createtable = reader.GetString(1);
86                             extendedProperties.Add(new ExtendedProperty("CS_CreateTableScript", createtable, DbType.String));
87                         }
88 
89                         if (!reader.IsClosed)
90                             reader.Close();
91                     }
92 
93                     if (connection.State != ConnectionState.Closed)
94                         connection.Close();
95                 }
96             }
97 
98             return extendedProperties.ToArray();
99         }
最終修改完成的“GetExtendedProperties”方法

 

然後我們F6生成一個修改後的dll元件"SchemaExplorer.MySQLSchemaProvider.dll"。

找到預設的dll:“X:\...\CodeSmith\v7.0\SchemaProviders\SchemaExplorer.MySQLSchemaProvider.dll”,替.....不行,還是先備份一下。。。哈哈

 

然後替換。開啟重啟CodeSmith,再次生成。。。-_-# 我去!這是在逗我麼。

列說明全部獲取成功,但是表說明卻依舊獲取失敗!

 

再次回到Visual Studio中仔細看看整個方法,最後發現。。服了。它的這個方法的判斷邏輯是:

 1 public ExtendedProperty[] GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject)
 2 
 3 {
 4 
 5   List<要返回的東西>......
 6 
 7   if(schemaObject 是一個 ColumnSchema)// 如果是一個列物件
 8 
 9   {
10 
11     // 這裡面也就是我們剛剛改的,獲取列說明部分的程式碼
12 
13   }
14 
15   if(schemaObject 是一個 TableSchema)// 完全沒有注意下面的這個判斷,如果是一個表物件!!!
16 
17   {
18 
19     // 這裡也就是我們下面要動手腳的地方了。
20 
21   }
22 
23 }

 

廢話不多說。直接上這個方法最終的程式碼

  1         public ExtendedProperty[] GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject)
  2         {
  3             List<ExtendedProperty> extendedProperties = new List<ExtendedProperty>();
  4 
  5             if (schemaObject is ColumnSchema)
  6             {
  7                 ColumnSchema columnSchema = schemaObject as ColumnSchema;
  8 
  9                 string commandText = string.Format(@"SELECT EXTRA, COLUMN_DEFAULT, COLUMN_TYPE, COLUMN_COMMENT
 10                                                       FROM INFORMATION_SCHEMA.COLUMNS
 11                                                       WHERE TABLE_SCHEMA = '{0}' AND TABLE_NAME = '{1}' AND COLUMN_NAME = '{2}'",
 12                                                       columnSchema.Table.Database.Name, columnSchema.Table.Name, columnSchema.Name);
 13 
 14                 using (DbConnection connection = CreateConnection(connectionString))
 15                 {
 16                     connection.Open();
 17 
 18                     DbCommand command = connection.CreateCommand();
 19                     command.CommandText = commandText;
 20                     command.Connection = connection;
 21 
 22                     using (IDataReader reader = command.ExecuteReader(CommandBehavior.CloseConnection))
 23                     {
 24                         while (reader.Read())
 25                         {
 26                             string extra = reader.GetString(0).ToLower();
 27                             bool columndefaultisnull = reader.IsDBNull(1);
 28                             string columndefault = "";
 29                             if (!columndefaultisnull)
 30                             {
 31                                 columndefault = reader.GetString(1).ToUpper();
 32                             }
 33                             string columntype = reader.GetString(2).ToUpper();
 34                             string columncomment = reader.GetString(3);
 35 
 36                             bool isIdentity = (extra.IndexOf("auto_increment") > -1);
 37                             extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.IsIdentity, isIdentity, columnSchema.DataType));
 38 
 39                             if (isIdentity)
 40                             {
 41                                 /*
 42                                 MySQL auto_increment doesn't work exactly like SQL Server's IDENTITY
 43                                 I believe that auto_increment is equivalent to IDENTITY(1, 1)
 44                                 However, auto_increment behaves differently from IDENTITY when used
 45                                 with multi-column primary keys.  See the MySQL Reference Manual for details.
 46                                 */
 47                                 extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.IdentitySeed, 1, columnSchema.DataType));
 48                                 extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.IdentityIncrement, 1, columnSchema.DataType));
 49                             }
 50 
 51                             extendedProperties.Add(new ExtendedProperty("CS_ColumnDefaultIsNull", columndefaultisnull, DbType.Boolean)); // Added for Backwards Compatibility.
 52                             extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.DefaultValue, columndefault, DbType.String));
 53                             extendedProperties.Add(new ExtendedProperty("CS_ColumnDefault", columndefault, DbType.String)); // Added for Backwards Compatibility.
 54                             extendedProperties.Add(new ExtendedProperty(ExtendedPropertyNames.SystemType, columntype, DbType.String));
 55                             extendedProperties.Add(new ExtendedProperty("CS_ColumnType", columntype, DbType.String)); // Added for Backwards Compatibility.
 56                             extendedProperties.Add(new ExtendedProperty("CS_ColumnExtra", extra.ToUpper(), DbType.String));
 57                             extendedProperties.Add(new ExtendedProperty("CS_Description", columncomment, DbType.String));
 58                         }
 59 
 60                         if (!reader.IsClosed)
 61                             reader.Close();
 62                     }
 63 
 64                     if (connection.State != ConnectionState.Closed)
 65                         connection.Close();
 66                 }
 67             }
 68             if (schemaObject is TableSchema)
 69             {
 70                 TableSchema tableSchema = schemaObject as TableSchema;
 71                 string commandText = string.Format(@"SHOW CREATE TABLE `{0}`.`{1}`", tableSchema.Database.Name, tableSchema.Name);
 72 
 73                 using (DbConnection connection = CreateConnection(connectionString))
 74                 {
 75                     connection.Open();
 76 
 77                     DbCommand command = connection.CreateCommand();
 78                     command.CommandText = commandText;
 79                     command.Connection = connection;
 80 
 81                     using (IDataReader reader = command.ExecuteReader(CommandBehavior.CloseConnection))
 82                     {
 83                         while (reader.Read())
 84                         {
 85                             string createtable = reader.GetString(1);
 86                             extendedProperties.Add(new ExtendedProperty("TS_Description", createtable, DbType.String));
 87                             int engineIndex = createtable.LastIndexOf("ENGINE");
 88                             int commentIndex = createtable.LastIndexOf("COMMENT=");
 89                             string tableDescription = reader.GetString(0);
 90                             if (commentIndex > engineIndex)
 91                             {
 92                                 tableDescription = createtable.Substring(commentIndex + 9).Replace("'", "");
 93                             }
 94                             extendedProperties.Add(new ExtendedProperty("CS_Description", tableDescription, DbType.String));
 95 
 96                         }
 97 
 98                         if (!reader.IsClosed)
 99                             reader.Close();
100                     }
101 
102                     if (connection.State != ConnectionState.Closed)
103                         connection.Close();
104                 }
105             }
106 
107             return extendedProperties.ToArray();
108         }
最終的“GetExtendedProperties”方法

 

重新生成,替換。。。重啟CodeSmith,連結MySQL生成。。。。必然果斷Ok

 

 

網上當然也有很多例子,不過都是只處理了列的說明,沒有處理表的說明

我這個處理表說明是通過擷取已獲得的CreateTableScript裡面的資料,獲取的表說明。

 

碼字不容易,感覺不錯的話,請不要忘了點贊哦~(*^_^ *)

 

【本章來自 孤影'Blog:http://www.cnblogs.com/LonelyShadow碼字不容易,轉載請註明出處。】

 

相關文章