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:
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
然后我们点击生成,生成的代码如下图:
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:
1
|
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。
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:
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:
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:
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 ListextendedProperties = 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 }
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。
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 ListextendedProperties = 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 }
重新生成,替换。。。重启CodeSmith,链接MySQL生成。。。。必然果断Ok:
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~(*^_^ *)
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亲们。码字不容易,觉得不错的话记得点赞哦。。