Query builder ni nini na inahusianaje na Eloquent?

Question

Accepted Answer

**Query Builder** ya Laravel ni kiolesura kinachotiririka na kinachoweza kuunganishwa kwa kujenga na kuendesha queries za database bila kuandika SQL ghafi. **Eloquent imejengwa juu ya Query Builder** — models za Eloquent huitumia chini ya pazia, na queries za Eloquent zinaweza kutumia methods zote za Query Builder.

## Query Builder (kiwango cha database, kupitia DB facade)

```php
use Illuminate\Support\Facades\DB;

DB::table('users')
    ->where('active', true)
    ->where('age', '>', 18)
    ->orderBy('name')
    ->limit(10)
    ->get();                          // returns generic objects (not models)

DB::table('users')->where('id', 1)->update(['name' => 'X']);
DB::table('users')->insert(['name' => 'Ann']);
```

Query Builder hufanya kazi moja kwa moja na tables (ikirudisha objects za kawaida, si Eloquent models). Inaweza kuunganishwa na **hutumia parameter binding kiotomatiki** — kuzuia SQL injection.

## Eloquent hutumia methods zile zile zinazotiririka

```php
// Eloquent queries support ALL Query Builder methods (it's built on top)
User::where('active', true)
    ->where('age', '>', 18)
    ->orderBy('name')
    ->get();                          // returns User MODELS (with relationships, etc.)
```

Unapounganisha methods kwenye Eloquent model, unatumia Query Builder chini ya pazia — lakini unapata **models** (zenye relationships, accessors, na methods) badala ya objects za kawaida.

## Queries za hali ya juu (zote mbili huzihimili)

```php
DB::table('orders')
    ->join('users', 'orders.user_id', '=', 'users.id')   // joins
    ->select('orders.*', 'users.name')
    ->where('orders.total', '>', 100)
    ->groupBy('users.id')
    ->havingRaw('SUM(orders.total) > 1000')
    ->get();

User::where('role', 'admin')
    ->orWhere('role', 'editor')
    ->whereIn('status', ['active', 'pending'])
    ->get();
```

Zote mbili huhimili joins, aggregates, subqueries, na masharti tata.

## Lini kutumia ipi

```text
Eloquent (Model::...) → the default — get models with relationships/accessors/methods.
                        Best for most application logic.
Query Builder (DB::table) → when you want lightweight queries without model overhead,
                            complex reporting/aggregations, or to avoid loading models.
```

## Kwa nini ni muhimu

Kuelewa Query Builder na uhusiano wake na Eloquent ni muhimu kwa kufanya kazi kwa ufanisi na databases katika Laravel na kuchagua chombo sahihi kwa kila hali.

Ufahamu muhimu ni kwamba **Eloquent imejengwa juu ya Query Builder** — hivyo methods zinazotiririka na zinazoweza kuunganishwa unazotumia kwenye Eloquent models (`where`, `orderBy`, `join`, n.k.) ni za Query Builder, ikimaanisha kujifunza moja hukufundisha zote mbili.

Query Builder hutoa njia safi, salama dhidi ya SQL injection (kupitia parameter binding ya kiotomatiki) ya kujenga queries bila kuandika SQL ghafi, na Eloquent huongeza utendaji wa model (relationships, accessors, methods) juu yake.

Kujua **lini kutumia ipi** ndiyo ujuzi wa kivitendo: **Eloquent** kwa mantiki nyingi za programu (unapata model objects tajiri zenye relationships na tabia), na **Query Builder moja kwa moja** (`DB::table`) kwa queries nyepesi bila uzito wa model, ripoti/aggregations tata, au unapokuwa huhitaji models kamili — jambo ambalo linaweza kuwa na ufanisi zaidi kwa hali fulani.

Zote mbili hushughulikia queries tata (joins, aggregates, subqueries) kwa usalama kwa API ile ile inayotiririka.

Kuelewa Query Builder, jinsi Eloquent inavyojengwa juu yake, parameter binding salama inayoshirikiwa (kuzuia SQL injection), na uchaguzi kati yao ni maarifa muhimu kwa kuandika msimbo wa database wenye ufanisi na salama katika Laravel, kwa kuwa ufikiaji wa database ni kiini cha programu nyingi na kuchagua kiwango kinachofaa (Eloquent tajiri wa model dhidi ya Query Builder nyepesi) huathiri uwazi na utendaji.