PLINQO, which stands for Professional LINQ to Objects, is a collection of CodeSmith templates that are meant to replace and extend the LINQ to SQL designers that are included with Visual Studio 2008.
The templates have the following features.
There are several advantages to using the PLINQO templates over the Visual Studio designer. Here is a list of the main reasons:
Use the following steps to get started using the Linq to Sql templates.
The Dbml.cst template is used to create a LINQ to SQL dbml file. The file conforms to the Microsoft DbmlSchema.xsd schema. This is the same document that the LINQ to SQL designer uses. The generated dbml file from this template can also be edited from the LINQ to SQL designer.
The template will create a new file if it doesn't exist. If the file does exist, the template will read it in and update it. This allows you to make changes to the file and not have it overwrite if the template is re-ran. However, only some of the attributes are safe from overwriting. Here is a list of safe attributes. They will be listed as an xpath.
Safe Attributes to change in the Dbml file ...
Warning: Be aware that the template will drop tables, columns and associations that it did not find in the database.
Properties on the Dbml.cst template:
| Property | Description |
|---|---|
| CleanExpression | List of regular expressions to clean table, view, column and procedure names. Any matched text found will be removed from the name. |
| IgnoreList | List of regular expressions used to ignore tables, views and procedures when generating mapping. |
| IncludeFunctions | Include stored procedures and user functions in mapping. |
| IncludeViews | Include views in mapping. |
| SourceDatabase | The source database to generate the dbml file for. |
| ContextNamespace | The namespace to use for the context class file. |
| EntityNamespace | The namespace to use for the entity class files. |
| DbmlFile | The path to the dbml file to generate. |
The entities template generates the entity classes needed by LINQ. The classes are generated from a dbml file. You can modify the names for classes and properties by editing the dbml file. See Dbml.cst for a list of safe attributes to change in the dbml file.
The template will generate 2 files for every Type in the dbml file. One file will be the generated partial class that can not be changed as it is overwritten when the template is re-ran. It will have the following file name... <entity>.Generated.cs
The second file is a partial class that can be modified as it will not be re-generated. You can implement the partial methods in this file. Some partial method stubs are created by default. This file will be named... <entity>.cs
If you set the project file property on the template, the generated files will be added to the project. The file that can not be modified will be hidden under the file that can be changed.
Properties on the Entities.cst template:
| Property | Description |
|---|---|
| DbmlFile | The path to the dbml file used generate the entities from. |
| OutputDirectory | The folder to save the generated files. |
| ProjectFile | The Visual Studio project file to add the generated files to. |
The manager template is for helping you get started with business logic for the LINQ entities. The managers will have common queries that are created from keys and indexes on the table. The manager will also have rules for the entity properties to make sure required fields are not null and that the length of a string does not exceed the max length the column allows.
The template works by creating a second partial class that has a Manager property. The manager will then have a property for each entity that has a manager. Here is a sample of the syntax for using the managers:
SampleDataContext db = new SampleDataContext();
// use the primary key
Task task = db.Manager.Task.GetByKey(taskId);
// use a foreign key
var myTasks = db.Manager.Task.GetByAssignedID(userId);
// the methods return IQueryable so you can add expressions
var openTasks = db.Manager.Task.GetByStatusID(statusId).OrderBy(t => t.CreateDate);
The manager also provides a business rules engine to your entities. In addition to the default validation rules that are generated, you can add custom rules by implementing the AddRules partial method in the custom entity class.
static partial void AddRules()
{
// Rule allows the Name property to be a max of 150 characters.
RuleManager.AddShared<Task>(new LengthRule("Name", 150));
// Rule that validates the value of the property using regex.
RuleManager.AddShared<Task>(new RegexRule("Name", ".*"));
// Rule allows only users in certain security roles to update.
RuleManager.AddShared<Task>(new UpdateRule(
new string[] { "Administrator", "Updaters" }));
}
Properties on the Managers.cst template:
| Property | Description |
|---|---|
| SourceDatabase | The source database to keys and indexes from for generating the manager classes. |
| DbmlFile | The path to the dbml file used generate the manager classes from. |
| ManagerContextName | The class name of the DataContext that supports the managers. |
| ManagerDirectory | The folder to save the generated manager files. |
| ManagerNamespace | The namespace to use for the generated manager class files. |
| ProjectFile | The Visual Studio project file to add the generated files to. |
The queries template is an optional alternative to the manager template. If you don't want to use the manager framework, you can use this template to generate some common queries for an entity. While its possible to use both the manger and query templates, they do duplicate some functionality. The template works by generating an extension class for Table<Entity>. This allows the queries to be off the DataContext.
SampleDataContext db = new SampleDataContext();
Task task = db.Task.GetByKey(1);
This is an example of what the extension class looks like.
/// <summary>
/// The query extension class for Task.
/// </summary>
public static partial class TaskQueryExtension
{
/// <summary>
/// Gets an instance by the primary key.
/// </summary>
public static Task GetByKey(this Table<Task> entity, int taskID)
{
if (entity.Context.LoadOptions == null)
return Query.GetByKey.Invoke((SampleDataContext)entity.Context, taskID);
else
return entity.FirstOrDefault(t => t.TaskID == taskID);
}
/// <summary>
/// Gets a query by an index.
/// </summary>
public static IQueryable<Task> GetByStatusID(this Table<Task> entity, int statusID)
{
if (entity.Context.LoadOptions == null)
return Query.GetByStatusID.Invoke((SampleDataContext)entity.Context, statusID);
else
return entity.Where(t => t.StatusID == statusID);
}
#region Query
/// <summary>
/// A private class for lazy loading static compiled queries.
/// </summary>
private static partial class Query
{
internal static readonly Func<SampleDataContext, int, Task> GetByKey =
CompiledQuery.Compile(
(SampleDataContext db, int taskID) =>
db.Task.FirstOrDefault(t => t.TaskID == taskID));
internal static readonly Func<SampleDataContext, int, IQueryable<Task>> GetByStatusID =
CompiledQuery.Compile(
(SampleDataContext db, int statusID) =>
db.Task.Where(t => t.StatusID == statusID));
}
#endregion
}
Properties on the Queries.cst template:
| Property | Description |
|---|---|
| SourceDatabase | The source database to keys and indexes from for generating the manager classes. |
| DbmlFile | The path to the dbml file used generate the query classes from. |
| QueryDirectory | The folder to save the generated query extension files. |
| ProjectFile | The Visual Studio project file to add the generated files to. |
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