sqlite and zeos
lazarus / 16-Databases

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addr3ss · 2015-06-30 11:19

Hello!
I want to excute a select query and replace the result with a label
caption.I very searched but I did not find a clear way.Can anyone
explain it step by step?tnx

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Danyfirex · 2015-07-01 17:49

hi. maybe you must explain better. I think you can use update instead
of select.

Saludos

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addr3ss · 2015-07-02 08:46

No I want to select some data from DB.I added a Zconnection and setted
library and db type and database fields.then added a Zquery and setted
my query and connection.but i dont know how to assign query result to
a label caption.

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rvk · 2015-07-02 09:12

If your Zconnection and Zquery are set correctly you can do something
like this:

Code: [Select]  ZConnection1.Connect; // if your ZConnection is not
connected yet
  ZQuery1.Open;         // if your ZQuery with the select isn't open
yet

  // this will get the value from field 'your_desired_field' from the
first record
  Label1.Caption :=
ZQuery1.FieldByName('your_desired_field').asString;

  // if you have multiple records
  ZQuery1.Next;

  // this will get the value from field 'your_desired_field' from the
second record
  Label1.Caption :=
ZQuery1.FieldByName('your_desired_field').asString;


This wiki is for SqlDB but it's almost the same for Zeos (especially
for reading from a dataset):
http://wiki.freepascal.org/SqlDBHowto#How_to_read_data_from_a_table.3F

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jma_sp · 2015-07-02 09:48

Thanks rvk.

addr3ss you can also use TDBTEXT in the data controls tab. If
connection is OK and also Query Ok it must show some data. You can use
tdbnavigator to move across records, equivalent to the explanation of
rvk but more friendly visualy.

zquery1.next
zquery1.prev

The advantage of the response of rvk is that you can assign the code
directly at your own button for specific functions.

More information about this components:

http://lazarus-ccr.sourceforge.net/docs/lcl/dbctrls/tdbnavigator.html
http://lazarus-
ccr.sourceforge.net/docs/lcl/dbctrls/howtousedataawarecontrols.html

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addr3ss · 2015-07-03 10:19

Quote from: rvk on July 02, 2015, 11:12:09 amIf your Zconnection and
Zquery are set correctly you can do something like this:

Code: [Select]  ZConnection1.Connect; // if your ZConnection is not
connected yet
  ZQuery1.Open;         // if your ZQuery with the select isn't open
yet

  // this will get the value from field 'your_desired_field' from the
first record
  Label1.Caption :=
ZQuery1.FieldByName('your_desired_field').asString;

  // if you have multiple records
  ZQuery1.Next;

  // this will get the value from field 'your_desired_field' from the
second record
  Label1.Caption :=
ZQuery1.FieldByName('your_desired_field').asString;


This wiki is for SqlDB but it's almost the same for Zeos (especially
for reading from a dataset):
http://wiki.freepascal.org/SqlDBHowto#How_to_read_data_from_a_table.3F

tnx worked.