PHP loop to read from SQLite and write to arrays/JSON - php

Question

I have a SQLite3 database which contains 4 tables with 9 rows each.
I've tried to do each one of the arrays one-by-one, with basically the same code as below (everything in the foreach loop), and it worked fine. I guess I just made some stupid mistakes (I don't really use PHP, this is pretty much the only project I've used it in). I tried to fix it, but somehow PHP is not really friendly today.
Currently the code below returns a JSON with 4 empty arrays.
<?php
header('Content-type: application/json');
$db = new PDO('sqlite:whad.db')or die('Could not open database');
$arDaniel = array();
$arAndi = array();
$arDave = array();
$arSimon = array();
for ($j=0; $j < 4; $j++) {
$name;
$arr;
if (j == 0) {
$name = 'Daniel';
$arr = $arDaniel;
}
elseif (j == 1) {
$name = 'Andi';
$arr = $arAndi;
}
elseif (j == 2) {
$name = 'Dave';
$arr = $arDave;
}
elseif (j == 3) {
$name = 'Simon';
$arr = $arSimon;
}
$query = "SELECT Datum, ID, RR, RL, KB, BD, SD, KH, Reihenfolge FROM $name ORDER BY date(Datum)";
$i = 1;
foreach($res = $db->query($query) as $value) {
$curr = array();
array_push($curr["Datum"] = $value[0]);
array_push($curr["ID"] = $value[1]);
array_push($curr["RR"] = $value[2]);
array_push($curr["RL"] = $value[3]);
array_push($curr["KB"] = $value[4]);
array_push($curr["BD"] = $value[5]);
array_push($curr["SD"] = $value[6]);
array_push($curr["KH"] = $value[7]);
array_push($curr["Reihenfolge"] = $value[8]);
array_push($arr[$i] = $curr);
$i++;
}
}
$json = array(
"Daniel" => $arDaniel,
"Andi" => $arAndi,
"Dave" => $arDave,
"Simon" => $arSimon
);
echo json_encode($json);
$db = NULL;
?>
EDIT: Removed quotes around $curr.

Answer 1

You have many unnecassary variables with the same data.
You simply could do the following
<?php
header('Content-type: application/json');
$db = new PDO('sqlite:whad.db')or die('Could not open database');
$json = array(
"Daniel" => array(),
"Andi" => array(),
"Dave" => array(),
"Simon" => array()
);
foreach($json as $name => &$arr){
$query = "SELECT Datum, ID, RR, RL, KB, BD, SD, KH, Reihenfolge FROM $name ORDER BY date(Datum)";
$stmt = $db->query($query);
//now comes the trick, that you tell pdo to fecth them already as array
$arr = $stmt->fetchAll(PDO::FETCH_ASSOC);
}
unset($arr);
echo json_encode($json);
?>
Look at the first example here: http://php.net/manual/de/pdostatement.fetchall.php
Also note the & before $arr, which will handle the $arr variable as reference (also the unset, because after the last pass, it would still be set, this is just good style to clean up)
Update:
As in the other answer you have to use PDO::FETCH_ASSOC to get an array with only the index names.

Answer 2

There are more than one error in your code:
$arDaniel = array();
$arAndi = array();
$arDave = array();
$arSimon = array();
for ($j=0; $j < 4; $j++) {
$name; # <---
$arr; # <---
This sort of ‘declaration’ in php is unnecessary, you can remove $name and $arr (it's not an error, btw);
if (j == 0) { # <---
In the for loop you use $j, you can't use j here: replace it with $j (in php variables are ever prepended by $);
$name = 'Daniel';
$arr = $arDaniel; # <---
By this assignment, you want change the original array, but with this assignment by value, you in fact create a copy of $arDaniel, and new elements are added only to $arr, not to $arDaniel; to do this, you have to do an assignment by reference through & keyword: replace this (and following similar) line with $arr = &$arDaniel;
}
elseif (j == 1) { # <--- see above
$name = 'Andi';
$arr = $arAndi; # <--- see above
}
elseif (j == 2) { # <--- see above
$name = 'Dave';
$arr = $arDave; # <--- see above
}
elseif (j == 3) { # <--- see above
$name = 'Simon';
$arr = $arSimon; # <--- see above
}
$query = "SELECT Datum, ID, RR, RL, KB, BD, SD, KH, Reihenfolge FROM $name ORDER BY date(Datum)";
$i = 1; # <---
The query is formally correct, but I don't know your table structure. $i = 1; is unnecessary (see below);
foreach($res = $db->query($query) as $value) {
$curr = array();
array_push($curr["Datum"] = $value[0]); # <---
array_push($curr["ID"] = $value[1]); # <---
array_push($curr["RR"] = $value[2]); # <---
array_push($curr["RL"] = $value[3]); # <---
array_push($curr["KB"] = $value[4]); # <---
array_push($curr["BD"] = $value[5]); # <---
array_push($curr["SD"] = $value[6]); # <---
array_push($curr["KH"] = $value[7]); # <---
array_push($curr["Reihenfolge"] = $value[8]); # <---
array_push($arr[$i] = $curr); # <---
$i++; # <---
}
}
The array_push syntax is not correct (see manual page): the correct syntax is array_push( $existentArray, $newElement ). In addition, you can't use array_push to add an associative value, you can use it only for numeric key. Change $curr assignments simply in $curr['Datum'] = $value[0]; etc...
To append $curr to $arr, you have to change the line in array_push( $arr, $curr ) or (better, as php recommends if only one element is appended) $arr[] = $curr;. After these changes, the $i++; line can be deleted.
$json = array(
"Daniel" => $arDaniel,
"Andi" => $arAndi,
"Dave" => $arDave,
"Simon" => $arSimon
);
echo json_encode($json);
$db = NULL;
Now your script is clean (I hope).
Your script remain a bit redundant. You can simplify it in this way:
$array = array( 'Daniel'=>array(), 'Andi'=>array(), 'Dave'=>array(), 'Simon'=>array() );
foreach( $array as $key => &$val )
{
$query = "SELECT Datum, ID, RR, RL, KB, BD, SD, KH, Reihenfolge FROM $key ORDER BY date(Datum)";
$result = $db->query( $query );
$val = $result->fetchAll( PDO::FETCH_ASSOC );
}
$json = json_encode( $array );
echo $json;
By this way, you init an array with names as key, then, in a foreach loop by reference (&$val) you perform a sql query searching in table $key and you fetch all results directly in array (in this example the values are stored as associative arrays, like in your example, but you can use PDO::FETCH_OBJ to store data as object). At the end, you encode the array end echo it.
Edit:
I see a previous answer nearly identical to mine...
BTW, I leave mine because I have spent a lot of time to explain various errors...