UML Basic notations

UML is popular for its diagrammatic notations. We all know that UML is for visualizing, specifying, constructing and documenting the components of software and non software systems. Here theVisualization is the most important part which needs to be understood and remembered by heart.

Structural Things:

Graphical notations used in structural things are the most widely used in UML. These are considered as the nouns of UML models. Following are the list of structural things.

• Classes
• Interface
• Collaboration
• Use case
• Active classes
• Components
• Nodes

Class Notation:

UML class is represented by the diagram shown below. The diagram is divided into four parts.

• The top section is used to name the class.
• The second one is used to show the attributes of the class.
• The third section is used to describe the operations performed by the class.
• The fourth section is optional to show any additional components.

Classes are used to represent objects. Objects can be anything having properties and responsibility.

Object Notation:

The object is represented in the same way as the class. The only difference is the name which is underlined as shown below.

As object is the actual implementation of a class which is known as the instance of a class. So it has the same usage as the class.

Interface Notation:

Interface is represented by a circle as shown below. It has a name which is generally written below the circle.

Interface is used to describe functionality without implementation. Interface is the just like a template where you define different functions not the implementation. When a class implements the interface it also implements the functionality as per the requirement.

Collaboration Notation:

Collaboration is represented by a dotted eclipse as shown below. It has a name written inside the eclipse.

Collaboration represents responsibilities. Generally responsibilities are in a group.

Use case Notation:

Use case is represented as an eclipse with a name inside it. It may contain additional responsibilities.

Use case is used to capture high level functionalities of a system.

Actor Notation:

An actor can be defined as some internal or external entity that interacts with the system.

Actor is used in a use case diagram to describe the internal or external entities.

Initial State Notation:

Initial state is defined to show the start of a process. This notation is used in almost all diagrams.

The usage of Initial State Notation is to show the starting point of a process.

Final State Notation:

Final state is used to show the end of a process. This notation is also used in almost all diagrams to describe the end.

The usage of Final State Notation is to show the termination point of a process.

Active class Notation:

Active class looks similar to a class with a solid border. Active class is generally used to describe concurrent behaviour of a system.

Active class is used to represent concurrency in a system.

Component Notation:

A component in UML is shown as below with a name inside. Additional elements can be added wherever required.

Component is used to represent any part of a system for which UML diagrams are made.

Node Notation:

A node in UML is represented by a square box as shown below with a name. A node represents a physical component of the system.

Node is used to represent physical part of a system like server, network etc.

Behavioural Things:

Dynamic parts are one of the most important elements in UML. UML has a set of powerful features to represent the dynamic part of software and non software systems. These features include interactions and state machines.

Interactions can be of two types:

• Sequential (Represented by sequence diagram)
• Collaborative (Represented by collaboration diagram)

Interaction Notation:

Interaction is basically message exchange between two UML components. The following diagram represents different notations used in an interaction.

Interaction is used to represent communication among the components of a system.

Grouping Things:

Organizing the UML models are one of the most important aspects of the design. In UML there is only one element available for grouping and that is package.

Package Notation:

Package notation is shown below and this is used to wrap the components of a system.

Annotational Things:

In any diagram explanation of different elements and their functionalities are very important. So UML has notes notation to support this requirement.

Note Notation:

This notation is shown below and they are used to provide necessary information of a system.

Relationships

A model is not complete unless the relationships between elements are described properly. TheRelationship gives a proper meaning to an UML model. Following are the different types of relationships available in UML.

• Dependency
• Association
• Generalization
• Extensibility

Dependency Notation:

Dependency is an important aspect in UML elements. It describes the dependent elements and the direction of dependency.

Dependency is represented by a dotted arrow as shown below. The arrow head represents the independent element and the other end the dependent element.

Dependency is used to represent dependency between two elements of a system.

Association Notation:

Association describes how the elements in an UML diagram are associated. In simple word it describes how many elements are taking part in an interaction.

Association is represented by a dotted line with (without) arrows on both sides. The two ends represent two associated elements as shown below. The multiplicity is also mentioned at the ends (1, * etc) to show how many objects are associated.

Association is used to represent the relationship between two elements of a system.

Generalization Notation:

Generalization describes the inheritance relationship of the object oriented world. It is parent and child relationship.

Generalization is represented by an arrow with hollow arrow head as shown below. One end represents the parent element and the other end child element.

Generalization is used to describe parent-child relationship of two elements of a system.

Extensibility Notation:

All the languages (programming or modeling) have some mechanism to extend its capabilities like syntax, semantics etc. UML is also having the following mechanisms to provide extensibility features.

• Stereotypes (Represents new elements)
• Tagged values (Represents new attributes)
• Constraints (Represents the boundaries)

Extensibility notations are used to enhance the power of the language. It is basically additional elements used to represent some extra behaviour of the system. These extra behaviours are not covered by the standard available notations.

More details are found here

I found this information here, a great blog to follow

Finally relaxation from Custom paging logics

Finally Sql server 2012 CTP 1 has the power to handle paging.
A new feature named Ad-hoc Query Paging is introduced in new version of Sql Server.

SQL paging using ORDER BY OFFSET n ROWS and FETCH NEXT n ROWS ONLY


In previous versions of Microsoft SQL Server, like SQL Server 2005, SQL Server 2008, or in SQL Server 2008 R2 t-sql ORDER By clause was used to sort the returned result set from the SELECT part of the query.
The following sql query is an example to how Order By clause was used before SQL Server 2012 CTP 1, Denali version.

-- Return all rows from Person table sorted by BusinessEntityID
SELECT ID, FirstName, LastName
FROM Person.Person
ORDER BY ID




It will return all records from the table




T-SQL Paging in SQL Server 2012 with ORDER BY OFFSET n ROWS FETCH NEXT n ROWS ONLY

Now here is OFFSET in Order By clause, this is a new t-sql feature in SQL Server 2012 CTP 1.
If Offset is used in an ORDER BY clause the result set will ignore the first offset amount rows and will not return back to the client. But the rest will be included in the result set.

-- Return all rows except the first 10 rows
SELECT ID, FirstName, LastName
FROM Person.Person
ORDER BY ID
OFFSET 10 ROWS




The above t-sql Select statement returns all rows (Total Rows - 10). This is how OFFSET 10 ROWS works in ORDER BY clause







Now an other improvement in ORDER BY clause is FETCH NEXT 10 ROWS ONLY syntax.
This new feature enables sql developers to fetch only specified amount of rows in the returned result set of the sql Select statement.
Let's say if you are doing paging with 10 rows in every page, then use Fetch Next 10 Rows Only

-- Return 10 rows after skipping the first 10 rows
SELECT ID, FirstName, LastName
FROM Person.Person
ORDER BY ID
OFFSET 10 ROWS
FETCH NEXT 10 ROWS ONLY




Please note that Fetch Next n Rows Only cannot be used without Offset n Rows hint in Order By clause.
Otherwise new Microsoft SQL Server 2012 sql engine will throw the following error :
Msg 153, Level 15, State 2, Line 5
Invalid usage of the option NEXT in the FETCH statement.

SQL Paging with Variables used in ORDER BY OFFSET n ROWS FETCH NEXT n ROWS ONLY

Let's now use sql parameters for creating a more flexible t-sql paging select statement in SQL Server 2012, Denali databases.

DECLARE @PageNumber int = 3 -- 3th page
DECLARE @RowsCountPerPage int = 15 -- with 15 records per page

-- Returns @RowsCountPerPage rows
-- After skipping the first (@PageNumber - 1) * @RowsCountPerPage rows
SELECT ID, FirstName, LastName
FROM Person.Person
ORDER BY ID
OFFSET (@PageNumber - 1) * @RowsCountPerPage ROWS
FETCH NEXT @RowsCountPerPage ROWS ONLY

The diamond problem

The "diamond problem" (sometimes referred to as the "deadly diamond of death") is an ambiguity that arises when two classes B and C inherit from A, and class D inherits from both B and C. If D calls a method defined in A (and does not override the method), and B and C have overridden that method differently, then from which class does it inherit: B, or C?


It is called the "diamond problem" because of the logical shape of the class inheritance diagram in this situation. Here, class A is at the top, both B and C separately beneath it, and D joins the two together at the bottom to form a diamond shape.

Ref: Wikipedia

Loose Coupling and Tight coupling

Tight coupling is when a group of classes are highly dependent on one another.
This scenario arises when a class assumes too many responsibilities, or when one concern is spread over many classes rather than having its own class.
Loose coupling is achieved by means of a design that promotes single-responsibility and separation of concerns.
A loosely-coupled class can be consumed and tested independently of other (concrete) classes.
Interfaces are a powerful tool to use for decoupling. Classes can communicate through interfaces rather than other concrete classes, and any class can be on the other end of that communication simply by implementing the interface.

Tight Coupling:

class CustomerRepository
{
    private readonly Database database;

    public CustomerRepository(Database database)
    {
        this.database = database;
    }

    public void Add(string CustomerName)
    {
        database.AddRow("Customer", CustomerName);
    }
}

class Database
{
    public void AddRow(string Table, string Value)
    {
    }
}

Loose Coupling:

class CustomerRepository
{
    private readonly IDatabase database;

    public CustomerRepository(IDatabase database)
    {
        this.database = database;
    }

    public void Add(string CustomerName)
    {
        database.AddRow("Customer", CustomerName);
    }
}

interface IDatabase
{
    void AddRow(string Table, string Value);
}

class Database : IDatabase
{
    public void AddRow(string Table, string Value)
    {
    }
} 

Great article on Stack Implementation

http://blogs.msdn.com/b/ericlippert/archive/2009/05/04/the-stack-is-an-implementation-detail-part-two.aspx

By Eric Lippert

How find Sql objects used in procedures

SELECT DISTINCT so.name
FROM syscomments sc
INNER JOIN sysobjects so ON sc.id=so.id
WHERE sc.TEXT LIKE '%Products%'

Enable Claims based authentication on an existing web application in SharePoint

When you provision a web application in SharePoint 2010 you get the option to enable Claims based authentication. However, after the provisioning there's no option in the GUI to turn it on. PowerShell saves the day again with the option to change from classic to claims based authentication using the lines below.

$WebAppName = "http://test:8001"
$account = "Administrator" 
$wa = get-SPWebApplication $WebAppName
Set-SPwebApplication $wa –AuthenticationProvider (New-SPAuthenticationProvider) 

–Zone Default

The user running these command should be a member of the SharePoint_Shell_Access role on the config DB, and a member of the WSS_ADMIN_WPG local group.