C / C++ / MFC

28-Dec-05 0:42

If i have an access database with a table called "USER" with fields ID, AGE, NAME, ADDRESS, and i want address of all users with age = 23, a simple sql query will do (SELECT * FROM USER WHERE blah blah)..

But when I have data in a CSV File, how would i build this sql query? select * from what? Cry | :((

Any help or pointers in this direction is highly appreciated.

Rajesh R. Subramanian

You have an apple and me too. We exchange those and We have an apple each.
You have an idea and me too. We exchange those and We have two ideas each.

ThatsAlok28-Dec-05 0:56

ThatsAlok

28-Dec-05 0:56

Rajesh R. Subramanian wrote:
But when I have data in a CSV File, how would i build this sql query? select * from what?

Hi Rajesh,
csv file is nothing, just a comma seperated data and whole line denotes a record.
for executing query AFAIK, you have to import that in access and proceed in similiar way you mentioned above.

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

Rajesh R Subramanian28-Dec-05 17:27

28-Dec-05 17:27

Hi Alok,

ThatsAlok wrote:
csv file is nothing, just a comma seperated data

Thanks for your reply, but I too know its Comma separated text data. My concern is that it would be faster to use CSV instead of Access database.

ThatsAlok wrote:
you have to import that in access and proceed in similiar way you mentioned above.

Dude, I have exported values from Access and created the CSV because it would be faster. You are asking me to create a MDB out of it again Confused | :confused:

Best Regards,
Rajesh R. Subramanian

You have an apple and me too. We exchange those and We have an apple each.
You have an idea and me too. We exchange those and We have two ideas each.

ThatsAlok28-Dec-05 18:33

ThatsAlok

28-Dec-05 18:33

Rajesh R. Subramanian wrote:
created the CSV because it would be faster.

How Come ? Confused | :confused:

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

<color>Aljechin 28-Dec-05 18:39

<color>Aljechin

28-Dec-05 18:39

Rajesh is correct.

1. Create a CSV file by exporting 10000 records.
2. Perform data operation on your MDB and CSV file.
3. You will surely find csv to be faster since it is text based.

<color>Aljechin 28-Dec-05 18:48

<color>Aljechin

28-Dec-05 18:48

hi,
Use OpenRowSet for performing data operations on .CSV files. I do not know if you could edit data, but you could query for sure.

-- modified at 0:48 Thursday 29th December, 2005

Rajesh R Subramanian28-Dec-05 18:57

28-Dec-05 18:57

Thank you so much. That was the keyword I was looking for.

Regards,
Rajesh R. Subramanian

You have an apple and me too. We exchange those and We have an apple each.
You have an idea and me too. We exchange those and We have two ideas each.

mbcvamsidhar28-Dec-05 1:07

mbcvamsidhar

28-Dec-05 1:07

Hai,
CSV is just a text file...You cannot perform any operations on that.
I think you have to Convert that text File in Table/Excel Format..
For this ..first you have to check ...
1.weather your file is variable length/Fixed length....
(...means weather your file is following any format..or not)
2.How it is parsed...(with coma,semicolon, space,tab etc)

VamsiDhar.MBC
SoftwareEngineer

Rajesh R Subramanian28-Dec-05 17:30

28-Dec-05 17:30

mbcvamsidhar wrote:
CSV is just a text file...You cannot perform any operations on that.

Sir, it is possible to perform operations on that. Atleast query operations. This can be done by using the xls driver. (select * from Sheet1 where blah blah).

mbcvamsidhar wrote:
2.How it is parsed...(with coma,semicolon, space,tab etc)

CSV = Comma separated values. Parsed with comma.

Regards and Thanks
Rajesh R. Subramanian.

You have an apple and me too. We exchange those and We have an apple each.
You have an idea and me too. We exchange those and We have two ideas each.

mbcvamsidhar28-Dec-05 18:43

mbcvamsidhar

28-Dec-05 18:43

Sir, it is possible to perform operations on that. Atleast query operations. This can be done by using the xls driver. (select * from Sheet1 where blah blah).

Can you Give me the syntax ....how to connect..etc

Thanks and Rgds
VamsiDhar.MBC
SoftwareEngineer

basementman28-Dec-05 9:20

basementman

28-Dec-05 9:20

You can use the ODBC Text file driver to query the csv directly. However, it only gives you read access to the csv.

onwards and upwards...

Rajesh R Subramanian28-Dec-05 17:31

28-Dec-05 17:31

Yes master,

I am using the same. But what would be the sql query format? SELECT * FROM what WHERE ...

Thanks and Regards,
Rajesh R. Subramanian

You have an apple and me too. We exchange those and We have an apple each.
You have an idea and me too. We exchange those and We have two ideas each.

Getting MSAccess Table Information

basementman29-Dec-05 3:43

basementman

29-Dec-05 3:43

Example assumes that the CSV file is C:\Data\MyData.csv:

select * from C:\Data\MyData.csv

Also, using the ODBC DSN config utility, you can define the names and data types of the columns in the file. If you do this, you can access the column names in your sql statement and get back converted data types. Otherwise, I believe it just returns columns named F1, F2, F3, etc, all being varchar(255).

onwards and upwards...

-- modified at 9:44 Thursday 29th December, 2005

mbcvamsidhar27-Dec-05 23:59

mbcvamsidhar

27-Dec-05 23:59

Hai,
Iam developing VC application which Selects any .MDB Database(MS-Access).
The requirement is..My Application should popup the list of Tables which contains primaryKey.
Can you pls tell me how to the retreive each table information in Access. (From MS-SQL i acheived this..using SQLGetPrimaryKeys()).....!
But this API is not Supporting For Access...

VamsiDhar.MBC
SoftwareEngineer

i++ and i = i + 1

Nishad S27-Dec-05 23:12

Nishad S

27-Dec-05 23:12

Hi,

I looked at the asm code in VC Disassembly for the following codes:
i++;
i = i+1;

Both are same.

10: i++;
0040D75F mov eax,dword ptr [ebp-8]
0040D762 add eax,1
0040D765 mov dword ptr [ebp-8],eax
11: i = i+1;
0040D768 mov ecx,dword ptr [ebp-8]
0040D76B add ecx,1
0040D76E mov dword ptr [ebp-8],ecx

But I studied in my computer classes that i++ is faster than = i+1.

How?

Thank you.

- NS -

Prakash Nadar28-Dec-05 0:04

Prakash Nadar

28-Dec-05 0:04

it depends on the context.

like for example

k = somefunctioncall(i+1);<br />
i = i +1;

or

k = somefunctioncall(++i);

so here the secound one is faster than the first one

-Prakash
-Prakash

-- modified at 6:22 Wednesday 28th December, 2005

Colin Angus Mackay28-Dec-05 0:11

Colin Angus Mackay

28-Dec-05 0:11

It has been a while since I did any C++ admitidly, I'm sure that the second example will pass a difference value into somefunctioncall because i++ is a postfix operation, i is passed into the function then updated, while i+1 will evaluate first then get passed into the function.

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Prakash Nadar28-Dec-05 0:15

Prakash Nadar

28-Dec-05 0:15

yeah i know, I made the mistake Blush | :O

Thanks

<hr<span style="color:gray;size:15px;">-Prakash
-Prakash

ThatsAlok28-Dec-05 0:47

ThatsAlok

28-Dec-05 0:47

Mr.Prakash wrote:
Thanks

-Prakash
-Prakash

is my vision get blurred Smile | :)

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

Nishad S28-Dec-05 0:14

Nishad S

28-Dec-05 0:14

The asm is

11: ++i;
0040D788 mov ecx,dword ptr [ebp-8]
0040D78B add ecx,1
0040D78E mov dword ptr [ebp-8],ecx
12: i = i+1;
0040D791 mov edx,dword ptr [ebp-8]
0040D794 add edx,1
0040D797 mov dword ptr [ebp-8],edx
13: fun(i+1);
0040D79A mov eax,dword ptr [ebp-8]
0040D79D add eax,1
0040D7A0 push eax
0040D7A1 call @ILT+5(fun) (0040100a)
0040D7A6 add esp,4
14: fun(++i);
0040D7A9 mov ecx,dword ptr [ebp-8]
0040D7AC add ecx,1
0040D7AF mov dword ptr [ebp-8],ecx
0040D7B2 mov edx,dword ptr [ebp-8]
0040D7B5 push edx
0040D7B6 call @ILT+5(fun) (0040100a)
0040D7BB add esp,4
15: fun(i++);
0040D7BE mov eax,dword ptr [ebp-8]
0040D7C1 mov dword ptr [ebp-0Ch],eax
0040D7C4 mov ecx,dword ptr [ebp-0Ch]
0040D7C7 push ecx
0040D7C8 mov edx,dword ptr [ebp-8]
0040D7CB add edx,1
0040D7CE mov dword ptr [ebp-8],edx
0040D7D1 call @ILT+5(fun) (0040100a)
0040D7D6 add esp,4

There are more instructions where ++ operator is used. Then how can we say that ++ is faster?

- NS -

vikas amin28-Dec-05 0:25

vikas amin

28-Dec-05 0:25

U r wrong the case is vice versa
Tough to Belive

Assembly code to prove my observations

<br />
507:  Add(++i);<br />
004010CE   mov         eax,dword ptr [ebp-4]<br />
004010D1   add         eax,1<br />
004010D4   mov         dword ptr [ebp-4],eax<br />
004010D7   mov         ecx,dword ptr [ebp-4]<br />
004010DA   push        ecx<br />
004010DB   call        @ILT+15(Add) (00401014)<br />
004010E0   add         esp,4<br />
508:  Add(i+1);<br />
004010E3   mov         edx,dword ptr [ebp-4]<br />
004010E6   add         edx,1<br />
004010E9   push        edx<br />
004010EA   call        @ILT+15(Add) (00401014)<br />
004010EF   add         esp,4<br />

506:  Add(1+i);<br />
004010CE   mov         eax,dword ptr [ebp-4]<br />
004010D1   add         eax,1<br />
004010D4   push        eax<br />
004010D5   call        @ILT+15(Add) (00401014)<br />
004010DA   add         esp,4<br />
507:  Add(i++);<br />
004010DD   mov         ecx,dword ptr [ebp-4]<br />
004010E0   mov         dword ptr [ebp-5Ch],ecx<br />
004010E3   mov         edx,dword ptr [ebp-5Ch]<br />
004010E6   push        edx<br />
004010E7   mov         eax,dword ptr [ebp-4]<br />
004010EA   add         eax,1<br />
004010ED   mov         dword ptr [ebp-4],eax<br />
004010F0   call        @ILT+15(Add) (00401014)<br />
004010F5   add         esp,4

AS far as i think this is compiler dependent
i dont know the reason

But this is surely true if we pass some object in function
as lots of mechanismis involved to create and destroy object

Vikas Amin
Embin Technology
Bombay
vikas.amin@embin.com