Dbml文件提取建表TSql-CodeSmith

时间：2010-09-27 来源：破浪

在昨天一个大学师弟，他问我能不能将LinqToSql文件转化为创建表的TSql语句，他是刚开始学习.NET，所以在网上下些示例看，但苦于没有数据库。所以就有了这一篇博客，作为我的Code生成技术的CodeSimth的最后一篇示例。在下一步Code 生成技术将转到Microsoft的T4模板，Code生成技术目前完成的有CodeDom,CodeSmith模板，高手请不要拍砖，请直接跳过。

在Linq2Sql的Dbml文件其实就是一个Xml文件，记录着数据库与生成Linq2SqlCode的数据信息，所以转化为TSql没有什么说的。我们需要提取其中的数据库信息，在转化为我们的Tsql，在这里建立了DBTable、DBColumn、DBAssociation三个实体类：

代码   1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5
  6 namespace DbmlToTable
  7 {
  8     public class DBTable
  9     {
10
11         public DBTable()
12         {
13             Columns = new List<DBColumn>();
14             this.Associations = new List<DBAssociation>();
15         }
16
17         public string TableName
18         {
19             get;
20             set;
21         }
22
23         public List<DBColumn> Columns
24         {
25             get;
26             set;
27         }
28
29         public List<DBAssociation> Associations
30         {
31             get;
32             set;
33         }
34
35     }
36
37     public class DBColumn
38     {
39         public string Name
40         {
41             get;
42             set;
43         }
44
45         public string DBType
46         {
47             get;
48             set;
49         }
50
51         public bool IsPrimaryKey
52         {
53             get;
54             set;
55         }
56
57         public bool IsDbGenerated
58         {
59             get;
60             set;
61         }
62
63         public bool CanBeNull
64         {
65             get;
66             set;
67         }
68     }
69
70     public class DBAssociation
71     {
72         public string Name
73         {
74             get;
75             set;
76         }
77
78         public string ThisKey
79         {
80             get;
81             set;
82         }
83
84         public string OtherKey
85         {
86             get;
87             set;
88         }
89
90         public bool IsForeignKey
91         {
92             get;
93             set;
94         }
95     }
96
97     public class DBTableHlper
98     {
99         public static DBTable GetAssociationTable(List<DBTable> collection,string assName)
100         {
101
102             return collection.Find(t => t.Associations.Find(a => !a.IsForeignKey && a.Name == assName) != null);
103         }
104     }
105 }
106
107

其中DBTableHlper是由于我的Codesimth是2.0版本的，不能用lamdam表达式，所以我将它编译在程序集里面。

建立了一个将我们的dbml文件xml Document转化为实体类辅助类：

代码 1 using System;
2 using System.Collections.Generic;
3 using System.Linq;
4 using System.Text;
5 using System.Xml;
6 using System.Xml.Linq;
7
8 namespace DbmlToTable
9 {
10
11     public interface IDbTableCollectionHelper
12     {
13         List<DBTable> Transport(XElement element);
14     }
15
16     public class DbTableCollectionHelper : IDbTableCollectionHelper
17     {
18         #region IDbTableCollectionHelper 成员
19
20         public List<DBTable> Transport(XElement element)
21         {
22             List<DBTable> collection = new List<DBTable>();
23             var tables = element.Elements(XName.Get("Table", "http://schemas.microsoft.com/linqtosql/dbml/2007%22));
24             foreach (var tab in tables)
25             {
26                 DBTable t = new DBTable() { TableName = tab.Attribute("Name").Value };
27                 var cols = tab.Element(XName.Get("Type", "http://schemas.microsoft.com/linqtosql/dbml/2007%22)).Elements(XName.Get(%22Column%22, "http://schemas.microsoft.com/linqtosql/dbml/2007%22));
28                 foreach (var col in cols)
29                 {
30                     DBColumn c = new DBColumn()
31                     {
32                         CanBeNull = col.Attribute("CanBeNull") != null ? col.Attribute("CanBeNull").Value.ToLower() == "true" : false,
33                         DBType = col.Attribute("DbType") != null ? col.Attribute("DbType").Value : "",
34                         IsDbGenerated = col.Attribute("IsDbGenerated") != null ? col.Attribute("IsDbGenerated").Value.ToLower() == "true" : false,
35                         IsPrimaryKey = col.Attribute("IsPrimaryKey") != null ? col.Attribute("IsPrimaryKey").Value.ToLower() == "true" : false,
36                         Name = col.Attribute("Name") != null ? col.Attribute("Name").Value : ""
37                     };
38                     t.Columns.Add(c);
39                 }
40
41                 var ass = tab.Element(XName.Get("Type", "http://schemas.microsoft.com/linqtosql/dbml/2007%22)).Elements(XName.Get(%22Association%22, "http://schemas.microsoft.com/linqtosql/dbml/2007%22));
42                 foreach (var item in ass)
43                 {
44                     DBAssociation a = new DBAssociation()
45                     {
46                         Name = item.Attribute("Name") != null ? item.Attribute("Name").Value : "",
47                         OtherKey = item.Attribute("OtherKey") != null ? item.Attribute("OtherKey").Value : "",
48                         ThisKey = item.Attribute("ThisKey") != null ? item.Attribute("ThisKey").Value : "",
49                         IsForeignKey = item.Attribute("IsForeignKey") != null ? item.Attribute("IsForeignKey").Value.ToLower() == "true" : false
50                     };
51                     t.Associations.Add(a);
52                 }
53                 collection.Add(t);
54             }
55             return collection;
56         }
57
58         #endregion
59     }
60 }
61
62

在转化为我们的实体类，我们剩下的就是编写我们的CodeSmith模板了（更多知识可以参考CodeSmith模板）：

代码 1 <%@ CodeTemplate Language="C#" TargetLanguage="Text" Src="" Inherits="" Debug="False" Description="Template description here." %>
2
3 <%@ Import NameSpace="System" %>
4 <%@ Import NameSpace="System.Xml" %>
5 <%@ Import NameSpace="System.Text" %>
6 <%@ Import NameSpace="System.Collections.Generic" %>
7 <%@ Assembly Name="DbmlToTable" %>
8
9 --Code By Wolf
10 <script runat="template">
11 private List<DbmlToTable.DBTable> _DbTableCollection;
12 public List<DbmlToTable.DBTable> DbTableCollection
13 {
14     get
15     {
16         return _DbTableCollection;
17     }
18     set
19     {
20         _DbTableCollection=value;
21     }
22 }
23
24 public  string GeneratorTableSql(List<DbmlToTable.DBTable> collection)
25 {
26     StringBuilder sb = new StringBuilder();
27     StringBuilder sbAssocation = new StringBuilder();
28     foreach (DbmlToTable.DBTable item in collection)
29     {
30         List<string> cols = new List<string>();
31         foreach (DbmlToTable.DBColumn  col in item.Columns)
32         {
33             cols.Add(string.Format("{0} {1} {2} ", col.Name, col.DBType, col.IsPrimaryKey ? "PRIMARY KEY " : ""));
34         }
35         sb.AppendFormat("\r\nCREATE TABLE {0} \r\n(\r\n{1}\r\n)", item.TableName, string.Join(",\r\n", cols.ToArray()));
36
37         foreach (DbmlToTable.DBAssociation ass in item.Associations)
38         {
39             if (ass.IsForeignKey)
40             {
41                 DbmlToTable.DBTable tab = DbmlToTable.DBTableHlper.GetAssociationTable(collection,ass.Name);
42                 if (tab != null)
43                 {
44                     sbAssocation.AppendLine();
45                     sbAssocation.AppendFormat(@"ALTER TABLE {0}  WITH NOCHECK ADD  CONSTRAINT {1} FOREIGN KEY({2}) REFERENCES {3} ({4})",
46                         item.TableName, "FK_" + ass.Name, ass.ThisKey, tab.TableName, ass.OtherKey);
47                 }
48             }
49         }
50     }
51
52     return sb.ToString() + "\r\n" + sbAssocation.ToString();
53 }
54 </script>
55 <%= this.GeneratorTableSql(_DbTableCollection) %>
56
57

在codeSimth中我们建立了一个集合属性传递实体类DBTable和一个转化TSql辅助方法.

在控制台调用编译模板以及输出：

代码 1 using System;
2 using System.Collections.Generic;
3 using System.Linq;
4 using System.Text;
5
6 namespace DbmlToTable
7 {
8     class Program
9     {
10         static void Main(string[] args)
11         {
12             IDbTableCollectionHelper helper = new DbTableCollectionHelper();
13             List<DBTable> collection = helper.
14                 Transport(System.Xml.Linq.XElement.
15
16          Load(@"xxpath\MultipleDocument.Data\MultipleDocumentDB.dbml"));
17
18             CodeSmith.Engine.CodeTemplate template = CodeSimthTemplateHelper.
19                 CompileTemplate(@"DBMLToTable.cst", w => Console.WriteLine(w));
20             if (template != null)
21             {
22                 CodeSimthTemplateHelper.AddPropertyParams(template, new { DbTableCollection = collection });
23                 string str = template.RenderToString();
24                 Console.WriteLine(str);
25                 //System.IO.File.AppendAllText(@"D:\1.sql", str);
26             }
27             Console.Read();
28         }
29
30 }
31
32
33
34

在CodeSimth中就是这么简单，生成相应的模板代码（个人理解CodeSmith就是把代码作为字符串输出）。

在上面到我的CodeSmith模板编译辅助类，在上一篇通过代码生成机制实现强类型编程-CodeSmith版也有，在这里也附带上：需要引用CodeSmith.Engine.dll.

代码 1 using System;
2
3 using System.Collections.Generic;
4
5 using System.Linq;
6
7 using System.Text;
8
9 using CodeSmith.Engine;
10
11 using Wolf.NameValueDictionary;
12
13 namespace DbmlToTable
14
15 {
16
17 public class CodeSimthTemplateHelper
18
19 {
20
21      public static CodeTemplate CompileTemplate(string templateName, Action errorWriter)
22
23      {
24
25            CodeTemplateCompiler compiler = new CodeTemplateCompiler(templateName); compiler.Compile();
26
27           if (compiler.Errors.Count == 0)
28
29            {
30
31            return compiler.CreateInstance();
32
33            }
34
35        else
36
37          {
38
39            for (int i = 0; i < compiler.Errors.Count; i++)
40
41         {
42
43             errorWriter(compiler.Errors[i].ToString());
44
45          }
46
47         return null;
48
49        }
50
51 }
52
53
54
55 public static void AddPropertyParams(CodeTemplate template,object param)
56
57 {
58
59       NameValueDictionary dict = new NameValueDictionary<object>(param);
60
61        AddPropertyParams(template, dict);
62
63 }
64
65
66
67 public static void AddPropertyParams(CodeTemplate template, NameValueDictionary<object> param)
68
69 {
70
71           NameValueDictionary<object> dict = new NameValueDictionary<object>(param);
72
73           foreach (var item in dict.Keys)
74
75           {
76
77                 template.SetProperty(item, dict[item]);
78
79            }
80
81 }
82
83 }
84
85 }
86