Yes, it is slow actually. But I could not do it with SQL. I wish I could do
more with SQL than code, which would give a good performance improvement.
>From overall application point of view, I may be considering using threads to
>read from database, so that the performance will be improved a bit.
On 30/07/2013, at 4:26 PM, "Stadin, Benjamin"
<benjamin.sta...@heidelberg-mobil.com> wrote:
> That can work, if performance is of no concern. Otherwise it will become
> miserably slow.
>
>
> Von: Fehmi Noyan ISI <fnoyan...@yahoo.com>
> Antworten an: Fehmi Noyan ISI <fnoyan...@yahoo.com>
> Datum: Dienstag, 30. Juli 2013 01:54
> An: Benjamin Stadin <benjamin.sta...@heidelberg-mobil.com>, General
> Discussion of SQLite Database <sqlite-users@sqlite.org>
> Betreff: Re: [sqlite] Comparing two tables column by column
>
> The approach I am using to compare tableA_old and tableA_new is;
>
> typedef struct container_t {
> // a structure to pass parameters into callbacks
> } container;
>
> static int callback_2(){
> // compare two values in the resulting table if they are different
> // write them into a resulting file
> }
>
> static int callback_1(){
> for (each column){
> char sql[256];
> sprintf(sql,"select %s from tableA_old where
> pkey=%s",columnName,primarykey);
> sqlite3_exec(db,sql,callback_2,,)
> }
> }
>
> int main(){
> // import CS file into DB
> // for each pair of files (each file is a table and files have
> // the same column names in the same order). Actually, these are
> // records for different dates
> char sql[256] = "select * from tableA_new;";
> container c;
> sqlite3_exec(db,sql,callback_1,(void*)c,null)
>
> }
> From: "Stadin, Benjamin" <benjamin.sta...@heidelberg-mobil.com>
> To: Fehmi Noyan ISI <fnoyan...@yahoo.com>; General Discussion of SQLite
> Database <sqlite-users@sqlite.org>
> Sent: Tuesday, July 30, 2013 9:00 AM
> Subject: Re: [sqlite] Comparing two tables column by column
>
> If you like ruby, I have another idea to get you going (maybe without
> needing to write much code):
>
> - Use a registered function to SQLite to create MD5 or SHA1 keys for rows
> in the table. Here is a ruby snippet that registers a SHA1 function:
> http://www.copiousfreetime.org/articles/2009/01/10/writing-sql-functions-in
> -ruby.html
> - Join both tables by your primary key and select those where the SHA keys
> don't match
> - go threw each column programmatically in your ruby code and simply
> compare column values with each other
>
> If you then need performance and get by some means a trigger for your
> newly inserted records, add a sha1 field to all of your tables and
> precompute and index the sha1 for each table.
>
> Benjamin Stadin
>
> Am 30.07.13 01:07 schrieb "Fehmi Noyan ISI" unter <fnoyan...@yahoo.com>:
>
> >EXCEPT query gave the different rows in tables, but what I am after is
> >the different values for existing records.
> >
> >The column names are exactly the same, however the number of rows may
> >differ (with most of the records are the same).
> >
> >
> >________________________________
> > From: Simon Slavin <slav...@bigfraud.org>
> >To: General Discussion of SQLite Database <sqlite-users@sqlite.org>
> >Sent: Monday, July 29, 2013 9:10 PM
> >Subject: Re: [sqlite] Comparing two tables column by column
> >
> >
> >
> >On 29 Jul 2013, at 12:36pm, Fabian Klebert
> ><f.kleb...@klebert-engineering.de> wrote:
> >
> >> Wouldn't
> >>
> >> SELECT * FROM table1
> >> EXCEPT
> >> SELECT * FROM table2
> >>
> >> solve this problem?
> >> I think it does for the example provided. Not sure if it would work in
> >>real-world environment.
> >
> >There are two elements: making sure the same rows are present, and making
> >sure the contents of the rows match. I would probably use EXCEPT
> >commands to find out entries in one database which weren't in the other,
> >then use INTERSECT command to check that the fields in the rows which
> >were in both. But that's just at first glance.
> >
> >Simon.
> >_______________________________________________
> >sqlite-users mailing list
> >sqlite-users@sqlite.org
> >http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
> >_______________________________________________
> >sqlite-users mailing list
> >sqlite-users@sqlite.org
> >http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
>
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