How to create a numeric only Text box

Add the following code in the textBox_KeyPress event:

If  (Not Char.IsNumber(e.KeyChar) And (e.KeyChar <> ChrW(Keys.Back))) Then

      e.Handled = True
End If

Column Names in upper case for Oracle subquery

Oracle is case-insensitive for table and column names in queries but the data dictionary records names in uppercase.

check out this example below:

select User_Number, User_Description from (
select user_id as "User_Number", User_name as "User_Description" from users_tbl);

The above query returns error as below:

ORA-00904: "USER_DESCRIPTION": invalid identifier
00904. 00000 -  "%s: invalid identifier"

Corrected query:

select USER_NUMBER, USER_DECSRIPTION from (
select user_id as "USER_NUMBER", User_name as "USER_DECSRIPTION" from users_tbl);

Loose Coupling - Good Discussion

http://forums.asp.net/t/944241.aspx/1?Loose+%20coupling

A good article on Interfaces
http://dotnet.dzone.com/articles/c-interfaces-what-are-they-and

Same parameters used multiples times in Oracle Query

If we use same parameters multiple times in a query in oracle as shown in example, it errors out. We need to create another set of variables with same values.


Check the usage of parameters in the below example:
:fromDate
:toDate
:uname


:fromDate1
:toDate1
:uname1



:fromDate2
:toDate2
:uname2


All the above paramaters are having the same values.

For example:-

select user_name,call_reason from call_tbl, users_tbl where call_placed_dt between :fromdate and :toDate

and user_name = :uname order by user_description

FULL JOIN

select user_name,call_reason from call_mrs_tbl, users_tbl where call_placed_dt between :fromdate1 and :toDate1

and user_name = :uname1 order by user_description

FULL JOIN

select user_name,call_reason from call_tbl, users_tbl where call_placed_dt between :fromdate2 and :toDate2

and user_name = :uname2 order by user_description;

We cannot use the above query as below. It errors out saying invalid datatype.

select user_name,call_reason from call_tbl, users_tbl where call_placed_dt between :fromdate and :toDate

and user_name = :uname order by user_description

FULL JOIN

select user_name,call_reason from call_mrs_tbl, users_tbl where call_placed_dt between :fromdate and :toDate
and user_name = :uname order by user_description

FULL JOIN

select user_name,call_reason from call_tbl, users_tbl where call_placed_dt between :fromdate and :toDate
and user_name = :uname order by user_description;

Order of parameters matters in oracle query

Faced lots of time to figure out why my oracle query was erroring out. It was the order of the dynamic parameters in the query should match the order we pass the parameter with values.

For example:-
select user_name,call_reason from call_tbl, users_tbl where call_placed_dt between :fromdate and :toDate
and user_name = :uname order by user_description;

Here you can see three parameters :fromDate, :toDate & :uname. These parameters needs to be passed from C# using command object in the following order in which it is used in the query, which is as below:
1. :fromDate
2. :toDate
3. :uname

I was passing the parameters in the following order:


1. :uname
2. :fromDate
3. :toDate


Took me a while to figure out. These are some tips which can be used if you stumble across such error again, you need not waste much time to figure out.

Hope this helps others.