Numeric Output from string

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Can we get output from "(5000+400-300)*12/100" in vb.net but output should be in numeric format not string format.

Output should be 612
How can i get it bacause array is niot working here.

Posted 30-Aug-12 0:34am

Rohit rgdon

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OriginalGriff · Answer 1 · 2012-08-30T00:39:00

Solution 1

You need to evaluate the expression. Have a look at this: Runtime C# Expression Evaluator[^] - it's in C#, but all the principles hold the same for VB.

Posted 30-Aug-12 0:39am

OriginalGriff

Aarti Meswania · Answer 2 · 2012-08-30T00:48:00

Solution 2

there are 2 ways,
1. create function to resolve string & evalute it e.g. Runtime C# Expression Evaluator[^] as given in solution 1

2. if you are using sql server also, then

VB

equ= "(5000+400-300)*12/100"
cmd.commandtext="select " & equ
dim ans=cmd.executescalar()

Happy coding!
:)

Posted 30-Aug-12 0:48am

Aarti Meswania

Comments

Rohit rgdon 31-Aug-12 6:20am

But I am Using postgresql.

Thanks and Regards
Rohit Gupta

Aarti Meswania 31-Aug-12 6:29am

sorry, no experience for postgresql
but can you execute query 'select 1+2' = 3 in postgresql?
if it is then it will allow to execute 'select (5000+400-300)*12/100' also
please reply working in postgresql or not?

Rohit rgdon 31-Aug-12 6:33am

No This Query is not working in postgresql.so I have no posibility to execute it in backend???????

Aarti Meswania 31-Aug-12 6:38am

see this link,
http://www.postgresql.org/docs/8.0/static/functions-math.html
http://www.postgresql.org/docs/7.3/static/functions-math.html
http://www.postgresql.org/docs/7.1/static/functions-math.html
it shows possible
try without writing select just '1+2'
postgresql is database like sql so it is backend check how to execute equation in that else you have to use function in VB.net
in sql 'select 1+2' is working that's why i suggest

Rohit rgdon 31-Aug-12 6:38am

But it is executing select 1+2. not 'select 1+2'

Aarti Meswania 31-Aug-12 6:41am

ok it's working good I had put it in single quote so you can identify query
do not execute query with quotation
it's working now execute
select (5000+400-300)*12/100

if worked then from vb.net pass above statement as query for execution and take output in variable

Rohit rgdon 31-Aug-12 6:46am

yes it is working....

Aarti Meswania 31-Aug-12 6:48am

okfrom vb.net

equ= "(5000+400-300)*12/100"
cmd.commandtext="select " & equ
dim ans=cmd.executescalar()

means as you fetch data from database

Rohit rgdon 31-Aug-12 6:49am

Link's jo aapne mujhe bhaje hain. i have already seen those links i want some function like to execute "select fun('5000+12/100')".

Aarti Meswania 31-Aug-12 6:51am

select (5000+400-300)*12/100
worked in your database?

if yes then forget all
ok
and post a code how you fetch data from your database using vb.net?

Rohit rgdon 31-Aug-12 6:51am

yes i can fetch data from database but my whole calculation is going in a postgres function so i want to do this on back end not on front end.

Aarti Meswania 31-Aug-12 6:52am

what do you mean by back-end & front-end?

Rohit rgdon 31-Aug-12 6:53am

can u come on chat on gtalk.

Aarti Meswania 31-Aug-12 6:54am

sorry not allowed here

Rohit rgdon 31-Aug-12 6:54am

front end means the programming code side and back end means the database functionality side i want the whole code in postgres function not in vb.net code mam.

Aarti Meswania 31-Aug-12 6:59am

query will execute in back-end
but you have to give command to back-end from your front-end(VB.net)
how you connect with database using vb.net?

you were using some code like below

dim con as new sqlconnection
dim cmd as new sqlcommand
cmd.commandtext="select ..."
...

Rohit rgdon 31-Aug-12 6:59am

like same thing you do in sql server functions i am doing in postgresql. this is same as you have to execute this code in function which can have more than 200 rows i have to calculate all rows answers.

Rohit rgdon 31-Aug-12 7:03am

yaa you r right but for small queries but i have a function which is doing calculation of employee salary . but i have basic in other table so i fetch basic amount from that table and put it in formula like '[Basic]+[CA]+[DA]*1.47/100' and then i have to calculate the value......????????/

Aarti Meswania 31-Aug-12 7:13am

see below example,
dim basic = txtbasic.text
dim ca = txtca.text
dim da = txtda.text
dim equ = "select (" & basic & " + " & ca & " + " & da & ")" & " * 1.47/100"
cmd.commandtext = equ
dim ans=cmd.executescalar()

Rohit rgdon 31-Aug-12 7:04am

ok i have done and i will follow this.

Rohit rgdon 31-Aug-12 7:16am

thanks for the solution but that code which genrating String like "5000*12/100". is in postgres(database) function.

Aarti Meswania 31-Aug-12 7:18am

sorry but as I said I am not familiar with postgresql
you mean to say that values are in data base
basic,ca & da?

Rohit rgdon 31-Aug-12 7:22am

Yes Definitely database is same like sql server function.don't take it as postgres take it as your database or like sql server 2005/2008.values r genrating from database.

Aarti Meswania 31-Aug-12 7:22am

ok then
follow this
see below example,
dim basic = txtbasic.text
dim ca = txtca.text
dim da = txtda.text
dim equ = "select (" & basic & " + " & ca & " + " & da & ")" & " * 1.47/100"
cmd.commandtext = equ
dim ans=cmd.executescalar()

Rohit rgdon 31-Aug-12 7:23am

values of basic,da,ca genrating from database

Aarti Meswania 31-Aug-12 7:24am

dim equ = "select (basic + ca + da )* 1.47/100 from tablename"

Rohit rgdon 31-Aug-12 7:24am

mam for this code first of all i have to execute function in back end then take it at front end then execute each row in back end then show the result it will so much time consuming

Rohit rgdon 31-Aug-12 7:36am

http://www.sendspace.com/file/vw1w8s

see this lnk then see the database table image at that link i think this will help you to understand my question.this is like values coming in sql server .

Aarti Meswania 31-Aug-12 7:51am

you have to use complex query
substring,replace,case in query to perform in backend only
better way is
see below example,

dim equ="[Basic]+[CA]+[DA]*1.47/100"
dim basic = txtbasic.text 'or getScalarValFromDB("select basic from tbl where empid=56")
dim ca = txtca.text
dim da = txtda.text
equ= equ.tolower.replace("[basic]",basic)
equ= equ.tolower.replace("[ca]",ca)
equ= equ.tolower.replace("[da]",da)

cmd.commandtext = "select " & equ
dim ans=cmd.executescalar()

Rohit rgdon 31-Aug-12 7:58am

have u seen that image which image link i have send you .becoz i think this code will not help me.

Aarti Meswania 31-Aug-12 7:59am

yes i have seen that and have also perform it in vb.net with sql using above code

Rohit rgdon 31-Aug-12 8:04am

but according to your code i have to display each employee basic,da,ca value in textbox then i have to calculate it but this code is good for 0-100 no but what about more then 100,500 people i think this code will work very slowly

Aarti Meswania 31-Aug-12 8:07am

that is hint how to do,
it's depends how you will assign value to basic & all other fields
if it's different for each employee then it is clear that for each employee you have to perform it

Aarti Meswania 31-Aug-12 8:08am

in your database you have not values of hr,da,basic in different columns but in rows

Rohit rgdon 31-Aug-12 8:12am

I have only basic value in database.i have value of basic like 1000 Rs. and other components have value according to basic value but when i do increment then basic become 1500 Rs. But all other components r formula based like PF '[Basic]*12/100'.so i have to calculate it according to new basic value in postgres function.

Aarti Meswania 31-Aug-12 8:14am

ok try to do that inside backend only
wish you will share if you solve it
best luck
Happy Coding!
:)

Rohit rgdon 31-Aug-12 8:16am

Ok!!!

Thanks And Regards!
Rohit Gupta

Aarti Meswania 31-Aug-12 8:17am

welcome :)

Rohit rgdon · Answer 3 · 2012-09-05T00:40:00

Solution 3

My question is solved .the solution is you have to make a function for like this (select '5000+1000'). which accept this string and calculate it then return value to you in numeric format.

Posted 5-Sep-12 0:40am

Rohit rgdon