Paramaterize Case Statement Using ODBC - php

Question

I am selecting data from an MS SQL DB using a similar query to this:
$result = odbc_prepare(
$connection,
"SELECT
t1.id, thumbnail, description, brand, vendor,
case
when ".implode(' AND ', $exactSearchTermDesc)." then 1
else 0
end as exactdescriptionmatch,
case
when ".implode(' AND ', $exactSearchTermMarkDesc)."". $exactThesaurusMarkDesc ."
then 1 else 0
end as exactcontentmatch,
case
when ".implode(' AND ', $searchTermDesc)."" . $thesaurusDesc ." then 1
else 0
end as descriptionmatch,
case
when ".implode(' AND ', $searchTermMarkDesc)."". $thesaurusMarkDesc ." then 1
else 0
end as contentmatch
FROM Martin.dbo.item_search"
);
odbc_execute($result);
How do I parameterize the variables in the case statements?
I tried, for example, just trying to paramaterize the first variable with this to no avail...
$exactSearchTermDesc = implode(' AND ', $exactSearchTermDesc);
$result = odbc_prepare(
$connection,
"SELECT
t1.id, thumbnail, description, brand, vendor,
case when ? then 1 else 0 end as exactdescriptionmatch,
case when ".implode(' AND ', $exactSearchTermMarkDesc)."". $exactThesaurusMarkDesc ." then 1 else 0 end as exactcontentmatch,
case when ".implode(' AND ', $searchTermDesc)."" . $thesaurusDesc ." then 1 else 0 end as descriptionmatch,
case when ".implode(' AND ', $searchTermMarkDesc)."". $thesaurusMarkDesc ." then 1 else 0 end as contentmatch
FROM Martin.dbo.item_search"
);
odbc_execute($result array($exactSearchTermDesc));
The variables are as below. $terms is the user input.
$searchTerms = explode(' ', $terms);
$exactSearchTermDesc = array();
$exactSearchTermMarkDesc = array();
$searchTermDesc = array();
$searchTermMarkDesc = array();
foreach ($searchTerms as $term) {
$term = trim($term);
if (!empty($term)) {
$exactSearchTermDesc[] = "description LIKE '$term %'";
$exactSearchTermMarkDesc[] = "contains(marketingDescription, '$term')";
$searchTermDesc[] = "description LIKE '%$term%'";
$searchTermMarkDesc[] = "marketingDescription LIKE '%$term%'";
$searchTermVendor[] = "vendor LIKE '%$term%'";
}
}
$exactThesaurusDesc = " Or " . implode(' AND ', $exactThesaurusDesc);
$exactThesaurusMarkDesc = " Or " . implode(' AND ', $exactThesaurusMarkDesc);
$thesaurusDesc = " Or " . implode(' AND ', $thesaurusDesc);
$thesaurusMarkDesc = " Or " . implode(' AND ', $thesaurusMarkDesc);
$thesaurusVendor = " Or " . implode(' AND ', $thesaurusVendor);

Answer 1

Consider re-factoring your SQL process. Rather than piecing together dynamic SQL components at application layer (i.e., PHP) that can impact readability and maintainability, consider multiple self-joins to a temp table of terms with below definition:
CREATE TABLE tmp_terms (
id IDENTITY(1,1) NOT NULL,
term VARCHAR(255),
thesauraus_indicator BIT
)
Specifically, run an aggregate query across joined matches where MIN returns 0 or 1. With this approach, the same SQL query is maintained but the underlying terms populated by PHP will be the dynamic component.
Below runs the non-thesaurus part of previous CASE logic. Also, since CONTAINS cannot use another column but only a literal value, JOIN expressions use LIKE with the leading and trailing wildcard.
SELECT
i.id, i.thumbnail, i.description, i.brand, i.vendor,
MIN(case
when exact_desc.term IS NOT NULL
then 1
else 0
end) AS exact_description_match,
MIN(case
when market_match.term IS NOT NULL
then 1
else 0
end) AS market_match,
MIN(case
when desc_match.term IS NOT NULL
then 1
else 0
end) AS desc_match,
MIN(case
when vendor_match.term IS NOT NULL
then 1
else 0
end) AS vendor_match
FROM Martin.dbo.item_search i
LEFT JOIN tmp_terms exact_desc
ON i.description LIKE CONCAT(exact_desc.term, ' %')
AND exact_desc.thesaurus_indicator = 0
LEFT JOIN tmp_terms market_match
ON i.marketingDescription LIKE CONCAT('%', market_match.term, '%')
AND market_match.thesaurus_indicator = 0
LEFT JOIN tmp_terms desc_match
ON i.description LIKE CONCAT('%', desc_match.term, '%')
AND desc_match.thesaurus_indicator = 0
LEFT JOIN tmp_terms vendor_match
ON i.vendor LIKE CONCAT('%', vendor_match.term, '%')
AND vendor_match.thesaurus_indicator = 0
GROUP BY i.id, i.thumbnail, i.description, i.brand, i.vendor
To integrate the thesaurus match, use UNION in CTE or subquery before aggregation in outer query.
WITH sub AS
(SELECT
i.id, i.thumbnail, i.description, i.brand, i.vendor,
exact_desc.term AS exact_desc_term, market_match.term AS market_match_term,
desc_match.term AS desc_match_term, vendor_match.term AS vendor_match_term
FROM Martin.dbo.item_search i
LEFT JOIN tmp_terms exact_desc
ON i.description LIKE CONCAT(exact_desc.term, ' %')
AND exact_desc.thesaurus_indicator = 0
LEFT JOIN tmp_terms market_match
ON i.marketingDescription LIKE CONCAT('%', market_match.term, '%')
AND market_match.thesaurus_indicator = 0
LEFT JOIN tmp_terms desc_match
ON i.description LIKE CONCAT('%', desc_match.term, '%')
AND desc_match.thesaurus_indicator = 0
LEFT JOIN tmp_terms vendor_match
ON i.vendor LIKE CONCAT('%', vendor_match.term, '%')
AND vendor_match.thesaurus_indicator = 0
UNION
SELECT
i.id, i.thumbnail, i.description, i.brand, i.vendor,
th_exact_desc.term, th_market_match.term,
th_desc_match.term, th_vendor_match.term
LEFT JOIN tmp_terms th_exact_desc
ON i.description LIKE CONCAT(th_exact_desc.term, ' %')
AND th_exact_match.thesaurus_indicator = 1
LEFT JOIN tmp_terms th_market_match
ON i.marketingDescription LIKE CONCAT('%', th_market_match.term, '%')
AND th_market_match.thesaurus_indicator = 1
LEFT JOIN tmp_terms th_desc_match
ON i.description LIKE CONCAT('%', th_desc_match.term, '%')
AND th_desc_match.thesaurus_indicator = 1
LEFT JOIN tmp_terms th_vendor_match
ON i.vendor LIKE CONCAT('%', th_vendor_match.term, '%')
AND th_vendor_match.thesaurus_indicator = 1
)
SELECT sub.id, sub.thumbnail, sub.description, sub.brand, sub.vendor,
MIN(case
when sub.exact_desc_term IS NOT NULL
then 1
else 0
end) AS exact_description_match,
MIN(case
when sub.market_match_term IS NOT NULL
then 1
else 0
end) AS market_match,
MIN(case
when sub.desc_match_term IS NOT NULL
then 1
else 0
end) AS desc_match,
MIN(case
when sub.vendor_match_term IS NOT NULL
then 1
else 0
end) AS vendor_match
FROM sub
GROUP BY sub.id, sub.thumbnail, sub.description, sub.brand, sub.vendor
Note: Above queries may need adjustment to final end use needs and testing. Performance may vary depending on number of search terms. But ultimately, the concept is to interact with data in sets and not long concatenated CASE WHEN... logic that grows with search terms.
Finally, in PHP simply clean out and populate the temp table with new values using parameterization and run any of the above final query:
odbc_exec($connection, "DELETE FROM tmp_terms");
$stmt = odbc_prepare($connection,
"INSERT INTO tmp_terms (term, thesaurus_indicator)
VALUES (?, ?)");
// NON-THESAURUS TERMS
foreach($search_terms as $t) {
odbc_execute($stmt, array($t, 0));
}
// THESAURUS TERMS
foreach($th_search_terms as $t) {
odbc_execute($stmt, array($t, 1));
}
// RUN FINAL SELECT QUERY
$result = odbc_exec($connection, "my_final_above_query");
while(odbc_fetch_row($result)){
for($i=1; $i<=odbc_num_fields($result); $i++){
// ... odbc_result($result,$i);
}
}