How to avoid duplicating a lot of php prepare 12+ times - php

Question

try {$db=mysqli_connect( etc )
catch {
retry on time out
handle errors
}
try { if (!($errors = $db->prepare("insert into errors (`insert`,`error`) values(?,?);
print "\n*********prepare Error:" . $db->error;
}
}
catch { repeat above}
try {$errors->bind_param("ss",$sqlLoad,$errormsg); }
catch {repeat above)
....
try {$error->execute()} catch {repeat above error handling}
Now repeat all of that 10-40 times for different SQL queries on different fields.
That is a lot of duplicated code. Make my code hard to read, and if someone wants to add more sql queries they are forced to reduplicate large blocks of code.
I was thinking something like this but ran into a stumbling block with bind.
$sql[0]=array("name","select ? from <tablename>","s");
$sql[1]=array("name","select ?,? from <tablename>","ss");
$sql[2]=array("name","select ?,?,? from <tablename>","sss");
$sql[3]=array("name","select ?,?,?,? from <tablename>","ssss");
for(i=0;i<=3,i++){
try (
$preQuery[$sql[i][0]=$db->prepare($sql[i][1]);}
catch {}
try {$preQuery[$sql[i][0]]->bind_param($sql[i][2],????);} //Here is the trouble how do I define unique variables
catch { }
}
Here is some real code
It is a work in progress
foreach ($fieldspath as $field)
{
$filepath=$_SERVER[$field];
$result=$queryfile->execute();
$getres = $queryfile->get_result();
$numRows = -1;
$numRows = $getres->num_rows;
if ($numRows <>0)
{
$qryField = $getres->fetch_assoc();
$_SERVER[$field]=$qryField["id"];
$fileCount=$qryField["count"];
$fileRating=$qryField["rating"];
mysqli_query($db, "update Files set count=count+1 where `id` ='" . $qryField["id"] . "';");
continue;
}
else
{
$output = $insertFile->execute();
$result = $queryip->execute();
$getres = $queryip->get_result();
$qryField = $getres->fetch_assoc();
$_SERVER[$field]=$qryField["id"];
}
}
Notice: How I can re-execute a query just by:
$result=$queryfile->execute();
The query doesn't have to be re-stated, nor do the parameters. Everything is automatic. The actual queries are all listed at the top of the program, and I never have to see them, or restate them ever again. Also I don't need to cram my parameters into array before I can use them.
<?php
$pipeName = '/var/run/mysql/mysql.sock';
$username = 'user';
$password = 'password';
$db = new PDO('mysql:unix_socket='.$pipeName.";dbname=dbase", $username, $password);
$sql["errors"]="insert into errors (`insert`,`error`) values(:insert,:error);";
$sql["events"]="insert into event (`message`) values(?);";
$sql["queryip"]="select id,count,rating FROM ip where address=? limit 1;";
$sql["queryUsrAgent"]="select id,count,rating FROM http_user_agent where agent=? limit 1;";
$sql["insUsrAgent"]="insert into http_user_agent (`agent`) values (?);";
$sql["insertIP"]="insert into ip (`address`) values (?);";
$sql["insertReqURI"]="insert into request (`REQUEST_URI`) values (?);";
$sql["queryReqURI"]="select * FROM request where REQUEST_URI=? LIMIT 1;";
$sql["queryfile"]="select id,count,rating FROM Files where path=? limit 1;";
$sql["insertFile"]="insert into Files (`path`) values (?);";
$sql["cntIp"]="update ip set count=count+1 where `address` = :ip";
$sql["cntFiles"]="update Files set count=count+1 where `id` = :id;";
$sql["cntAgent"]="update http_user_agent set count=count+1 where `agent` = :agent;";
$sql["reqRequest"]="select * FROM request where REQUEST_URI= :requesturi LIMIT 1;";
$sql["cntRequest"]="update request set count=count+1 where `REQUEST_URI` = :requesturi;";
$ready=doPrepare($db,$sql);
$ready["errors"]->execute(array("insert"=>"stuff","error" =>"stuff"));
pdoRun($ready,"errors",array("iniisert"=>"iiiii","error" =>"yyyyyggg"));
function doPrepare($db, $enmass) {
foreach ($enmass as $key => $sql) {
try {
$stmt[$key] = $db->prepare($sql);
} catch (PDOException $e) {
print "\nStuff";
trigger_error($e);
return false;
}
}
return $stmt;
}
function pdoRun($ready,$query,$vals) {
try {
$ready[$query]->execute($vals);
} catch (PDOException $e) {
print "\nExecution fail";
}
}
// $stmt->execute(array_values($column_values));
?>

Answer 1

Making prepared queries like you are doing doesn't work like you seem to think it does. The parameter placeholders can only substitute for literal values. You can't use them for column names or table names or anything else.
You also can't prepare a query like "select ? from" because it names no table. It's not a syntactically complete query.
The better practice is to code a "helper function" that does the prepare and execute for you. You can reduce repetitive code that way.
By the way, I find PDO is much easier than Mysqli when coding a helper function like this, because you don't have to use the bind_param() with variable arguments. In PDO, you just pass an array of arguments to execute().
function doInsert($db, $sql, $params) {
try {
$stmt = $db->prepare($sql);
$stmt->execute($params);
} catch (PDOException $e) {
trigger_error($e);
return false;
}
return true;
}
Now call it this way:
$sql = "insert into errors (`insert`, `error`) values(?, ?)";
$success = doInsert($db, $sql, [$sqlLoad, $errormsg]);
You might even like the function to format your INSERT statement for you:
function doInsert($db, $table, $column_values) {
$placeholders = array_fill(1, count($column_values), '?');
$columns = implode(',', array_keys($column_values));
$sql = "INSERT INTO `$table` ($columns) VALUES ($placeholders)";
try {
$stmt = $db->prepare($sql);
$stmt->execute(array_values($column_values));
} catch (PDOException $e) {
trigger_error($e);
return false;
}
return true;
}
Then call it like this:
$success = doInsert($db, "errors", ["insert"=>$sqlLoad, "error"=>$errormsg]);
You'll have to do something to apply back-ticks to the column names too.