完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案

问题描述:

  CodeSmith是现在比较实用的代码生成器,但是我们发现一个问题:

  使用CodeSmith编写MySQL模板的时候,会发现一个问题:MySQL数据表中的列说明获取不到,也就是column.Description。如图:

完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案_第1张图片

 

我们打开CodeSmith编写一个简单的Model实体类的示例模板如下:

 1 <%-- 
 2 Name:           MySQL Model实体模板
 3 Author:         孤影[QQ:778078163]
 4 Description:    CodeSmith连接MySQL生成Model实体模板
 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="目标数据表" %>
13 <%@ Property Name="ModelNamespace" Type="System.String" Description="Model实体所在的命名空间" %>
14 
15 using System;
16 using System.Collections.Generic;
17 using System.Linq;
18 using System.Text;
19 namespace <%=ModelNamespace %>
20 {
21     /// 
22     /// <%=SourceTable.Description %>
23     /// 
24     public class <%=SourceTable.Name %>
25     {
26         <%
27             // 循环遍历 获取当前数据表中的所有列
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 
一个简单的CodeSmith生成Model实体的模板

 

然后我们点击生成,生成的代码如下图:

完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案_第2张图片

 

当然,使用SQL Server及其他数据库都是可以获取到的,这是为什么呢?

 

逼的没招没招了的时候,果断打开.NET Reflector,看看CodeSmith对SQL Server和MySQL二者,数据表生成操作的时候,有什么不同的地方,或者有什么缺少的地方。

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

 

展开后,开始一个个找里面的方法,突然发现一个亮点:“GetTableColumns(string connectionString, TableSchema table);

这个字面的意思不就是获取列数据么?打开看看。。。可惜,里面只是根据表查询所有列,并没有Description相关操作。

 

继续找,继续对比。。。最终终于找到问题了:

方法“GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject);”里面的查询语句是:

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);

这个不就是获取Column列中的扩展属性的方法么?!

对比发现,SQL Server的dll里这个方法的下面,有返回Description,而MySQL正好没有!

 

二话不说,找到CodeSmith的源码包解压,翻出MySQL的项目:“X:\...\CodeSmith\v7.0\Samples\Samples\Projects\CSharp\MySQLSchemaProvider

然后打开Visual Studio载入"MySQLSchemaProvider.csproj",有很多错误,那是因为缺少了引用,添加CodeSmith\bin里面的相关引用即可。

 

完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案_第3张图片

 

需要引用的组件你可以在下面两个CodeSmith安装目录中找到:

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

 

添加引用之后,错误就全部没了:

完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案_第4张图片

 

然后我们果断开始修改代码、首先找到刚刚那个获取列扩展属性的方法:

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

 

然后我们根据观察SQL Server的代码,发现MySQL里面这个方法:

完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案_第5张图片

在SQL语句查询的时候少查询了一项数据:“COLUMN_COMMENT”,于是我们首先修改它查询的SQL语句如下:

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);

 

既然上面查询了,按照正常的数据查询流程,下面应该遍历读取,然后返回吧?

于是继续看,下面有一个while,正是将上面查询出来的数据返回的,我们对比SQL Server的代码发现:

完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案_第6张图片

上面查询出来的每一项,下面都有获取返回,而我们刚刚添加的那个“COLUMN_COMMENT”则没有进行数据获取、没有怎么办?加呗~

获取每个数据后,最后统一将封装在“extendedProperties”中,于是我们也将获取到的Description添加进去,其与步骤省略。最终修改的代码如下:

 1 public ExtendedProperty[] GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject)
 2         {
 3             List extendedProperties = new List();
 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         }
最终修改完成的“GetExtendedProperties”方法

 

然后我们F6生成一个修改后的dll组件"SchemaExplorer.MySQLSchemaProvider.dll"。

找到默认的dll:“X:\...\CodeSmith\v7.0\SchemaProviders\SchemaExplorer.MySQLSchemaProvider.dll”,替.....不行,还是先备份一下。。。哈哈

 

然后替换。打开重启CodeSmith,再次生成。。。-_-# 我去!这是在逗我么。

完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案_第7张图片

 

再次回到Visual Studio中仔细看看整个方法,最后发现。。服了。它的这个方法的判断逻辑是:

 1 public ExtendedProperty[] GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject)
 2 
 3 {
 4 
 5   List<要返回的东西>......
 6 
 7   if(schemaObject 是一个 ColumnSchema)// 如果是一个列对象
 8 
 9   {
10 
11     // 这里面也就是我们刚刚改的,获取列说明部分的代码
12 
13   }
14 
15   if(schemaObject 是一个 TableSchema)// 完全没有注意下面的这个判断,如果是一个表对象!!!
16 
17   {
18 
19     // 这里也就是我们下面要动手脚的地方了。
20 
21   }
22 
23 }

 

废话不多说。直接上这个方法最终的代码

  1         public ExtendedProperty[] GetExtendedProperties(string connectionString, SchemaObjectBase schemaObject)
  2         {
  3             List extendedProperties = new List();
  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         }
最终的“GetExtendedProperties”方法

 

重新生成,替换。。。重启CodeSmith,链接MySQL生成。。。。必然果断Ok

完美解决CodeSmith无法获取MySQL表及列Description说明注释的方案_第8张图片

 

 

网上当然也有很多例子,不过都是只处理了列的说明,没有处理表的说明

我这个处理表说明是通过截取已获得的CreateTableScript里面的数据,获取的表说明。

 

码字不容易,感觉不错的话,请不要忘了点赞哦~(*^_^ *)

 

【本章来自 孤影'Blog:http://www.cnblogs.com/LonelyShadow,码字不容易,转载请注明出处。】

 

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