XML and HTML

XML describe the data or we can say its like a database which get the data and helps in fetching the data on the other side HTML is use only for displayng the data so we can say HTML is static information display

What is Abstract Class

Classes that cannot be instantiated. We cannot create an object from such a class for use in our program. We can use an abstract class as a base class, creating new classes that will inherit from it. Creating an abstract class with a certain minimum required level of functionality gives us a defined starting point from which we can derive non-abstract classes. An abstract class may contain abstract methods & non-abstract methods. When a class is derived fr om an abstract class, the derived class must implement all the abstract methods declared in the base class. We may use accessibility modifiers in an abstract class.An abstract class can inherit from a non-abstract class. In C++, this concept is known as pure virtual method.

Which one is better WebService and Remoting

Both of these have little difference WebService helpfull where the user who is using WebService doesnot have the .NET plateform. On the otherside for remoting we need .Net plateform on the both side so from both of this remoting is faster then webservice.So keep in mind which of these are you using if you have .net plateform or other.

What do you mean by Attributes and Reflection

Attributes is a techniques for adding metadata, just like compiler instructions and other data about your data, methods, and classes, to the program itself. Attributes are inserted into the metadata and are visible through ILDasm and other metadata-reading tools. Reflection is the process from which a program can read metadata that of its own. A program is said to reflect on itself, extracting metadata from its assembly and using that metadata either to in

FAQ on Joins in SQL Server ????

1. What are joins?
Sometimes we have to select data from two or more tables to make our
result complete. We have to perform a join.

44. How many types of Joins?
Joins can be categorized as:
• Inner joins (the typical join operation, which uses some comparison
operator like = or <>). These include equi-joins and natural joins.
Inner joins use a comparison operator to match rows from two tables
based on the values in common columns from each table. For example,
retrieving all rows where the student identification number is the
same in both the students and courses tables.
• Outer joins. Outer joins can be a left, a right, or full outer join.
Outer joins are specified with one of the following sets of keywords
when they are specified in the FROM clause:
• LEFT JOIN or LEFT OUTER JOIN -The result set of a left outer join
includes all the rows from the left table specified in the LEFT OUTER
clause, not just the ones in which the joined columns match. When a
row in the left table has no matching rows in the right table, the
associated result set row contains null values for all select list
columns coming from the right table.

• RIGHT JOIN or RIGHT OUTER JOIN - A right outer join is the reverse
of a left outer join. All rows from the right table are returned. Null
values are returned for the left table any time a right table row has
no matching row in the left table.
• FULL JOIN or FULL OUTER JOIN - A full outer join returns all rows in
both the left and right tables. Any time a row has no match in the
other table, the select list columns from the other table contain null
values. When there is a match between the tables, the entire result
set row contains data values from the base tables.
• Cross joins - Cross joins return all rows from the left table, each
row from the left table is combined with all rows from the right
table. Cross joins are also called Cartesian products. (A Cartesian
join will get you a Cartesian product. A Cartesian join is when you
join every row of one table to every row of another table. You can
also get one by joining every row of a table to every row of itself.)

45. What is self join?
A table can be joined to itself in a self-join.

46. What are the differences between UNION and JOINS?
A join selects columns from 2 or more tables. A union selects rows.

what is normalization?

what is normalization?
Basically, it's the process of efficiently organizing data in a database. There are two goals of the normalization process: eliminate redundant data (for example, storing the same data in more than one table) and ensure data dependencies make sense (only storing related data in a table). Both of these are worthy goals as they reduce the amount of space a database consumes and ensure that data is logically stored.

The database community has developed a series of guidelines for ensuring that databases are normalized. These are referred to as normal forms and are numbered from one (the lowest form of normalization, referred to as first normal form or 1NF) through five (fifth normal form or 5NF). In practical applications, you'll often see 1NF, 2NF, and 3NF along with the occasional 4NF. Fifth normal form is very rarely seen.

First normal form (1NF) sets the very basic rules for an organized database:

- Eliminate duplicative columns from the same table.
- Create separate tables for each group of related data and identify each row with a unique column or set of columns (the primary key).

Second normal form (2NF) further addresses the concept of removing duplicative data:

- Remove subsets of data that apply to multiple rows of a table and place them in separate tables.
- Create relationships between these new tables and their predecessors through the use of foreign keys.

Third normal form (3NF) goes one large step further:

- Remove columns that are not dependent upon the primary key.

Finally, fourth normal form (4NF) has one requirement:

- A relation is in 4NF if it has no multi-valued dependencies.

Rules of Data Normalization

Eliminate Repeating Groups - Make a separate table for each set of related attributes, and give each table a primary key.

Eliminate Redundant Data - If an attribute depends on only part of a multi-valued key, remove it to a separate table.

Eliminate Columns Not Dependent On Key - If attributes do not contribute to a description of the key, remove them to a separate table.

Isolate Independent Multiple Relationships - No table may contain two or more 1:n or n:m relationships that are not directly related.

Isolate Semantically Related Multiple Relationships - There may be practical constrains on information that justify separating logically related many-to-many relationships.

Optimal Normal Form - a model limited to only simple (elemental) facts, as expressed in ORM.

Domain-Key Normal Form - a model free from all modification anomalies.

A small example:

DATA Name Company Company_Address urlA urlB mah AAA Street1 AAA.com BBB.com iham BBB strret2 AAA.com BBB.com

After First Normal Form

Table1 Id Name Company CompanyAddress Host 1 mah AAA Street1 AAA.com 1 mah AAA Street1 BBB.com 2 iham BBB strret2 AAA.com 2 iham BBB strret2 BBB.com

After Second Normal Form

Table2 Id Name Company CompanyAddress 1 mah AAA Street1 2 iham BBB strret2

Table3 P_Id F_Id Host 1 1 AAA.com 2 1 BBB.com 3 2 AAA.com 4 2 BBB.com

After Third Normal Form

Table4 Id Name RF_Id 1 mah 1 2 iham 2

Table5 PF_Id Company CompanyAddress 1 AAA Street1 2 BBB strret2

Table6 H_Id F_Id Host 1 1 AAA.com 2 1 BBB.com 3 2 AAA.com 4 2 BBB.com

Finally Data Relationships

Table7 Id Name RF_Id 1 mah 1 2 iham 2

Table8 PF_Id Company CompanyAddress 1 AAA Street1 2 BBB strret2

Table9 H_Id Host 1 AAA.com 2 BBB.com

Table10 HID FH_Id F_ID 1 1 1 2 1 2 3 2 1 4 2 2

The output tables are Table7, Table8, Table9 and Table10. Finally we have four tables.

How to Add controls at run time & fetch their values

here are so many situations in which we want to add controls at run time because we do'nt know the Exact number of controls that we have to add.

These two articles show this process with Source Code.

http://www.dotnetspider.com/kb/Article2627.aspx

http://www.dotnetspider.com/kb/Article2628.aspx