• Technical
Saturday, 9 May 2015
• Technical
.NET- Types of threading models in VB.net
- Types of compatability in VB and their usage
- Difference between CDATA and PCDATA in
XML
- What is Assync in XML api which version
of XML parser u worked with
- Types of ASP objects
- Difference between application and
session
- What is web application virtual directory
- Can two web application share a session
and application variable
- If i have a page where i create an
instance of a dll and without invoking any method can I send values to next
page
- Diffeernce between Active Exe and /Dll
- Can the dictionary object be created in
client’s ccope?
- About MTS and it’s purpose
- About writting a query and SP which is
better
- I have a component with 3 parameter and
deployed to client side now i changed my dll method which takes 4 parameter.How
can i deploy this without affecting the clent’s code
- How do you do multithreading application
in VB
- About Global .asax
- Connection pooling in MTS
- If cookies is disabled in clinet browser
will session work
- About XLST
- How do you attach an XSL to an XML in
presenting output
- What is XML
- How do you make your site SSL enabled
- Did you work on IIS adminisdtration
Saturday, 10 January 2015
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.
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.
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:
Outer joins are specified with one of the following sets of keywords when they are specified in the FROM clause:
INDEX
What is Index? It’s purpose?
Indexes in databases are similar to indexes in books. In a database, an index allows the database program to find data in a table without scanning the entire table. An index in a database is a list of values in a table with the storage locations of rows in the table that contain each value. Indexes can be created on either a single column or a combination of columns in a table and are implemented in the form of B-trees. An index contains an entry with one or more columns (the search key) from each row in a table. A B-tree is sorted on the search key, and can be searched efficiently on any leading subset of the search key. For example, an index on columns A, B, C can be searched efficiently on A, on A, B, and A, B, C.
Indexes in databases are similar to indexes in books. In a database, an index allows the database program to find data in a table without scanning the entire table. An index in a database is a list of values in a table with the storage locations of rows in the table that contain each value. Indexes can be created on either a single column or a combination of columns in a table and are implemented in the form of B-trees. An index contains an entry with one or more columns (the search key) from each row in a table. A B-tree is sorted on the search key, and can be searched efficiently on any leading subset of the search key. For example, an index on columns A, B, C can be searched efficiently on A, on A, B, and A, B, C.
Index Optimization tips
2 tables
Employee
|
Phone
|
empid
empname salary mgrid |
empid
phnumber |
Select all employees who doesn't have phone?
SELECT empname
FROM Employee
WHERE (empid NOT IN
(SELECT DISTINCT empid
FROM phone))
SELECT empname
FROM Employee
WHERE (empid NOT IN
(SELECT DISTINCT empid
FROM phone))
Transact-SQL Optimization Tips
Use views and stored procedures instead of
heavy-duty queries.
This can reduce network traffic, because your client will send to server only stored procedure or view name (perhaps with some parameters) instead of large heavy-duty queries text. This can be used to facilitate permission management also, because you can restrict user access to table columns they should not see.
This can reduce network traffic, because your client will send to server only stored procedure or view name (perhaps with some parameters) instead of large heavy-duty queries text. This can be used to facilitate permission management also, because you can restrict user access to table columns they should not see.
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