Analysis of CURD operations and coherent operations in Laravel framework database

This article mainly introduces the summary of CURD operations, coherent operations, and chain operations of the Laravel framework database. This article contains a large number of common methods of database operations. Friends in need can refer to the following

1. Selects

Retrieve all rows in the table

$users = DB::table('users')->get();
foreach ($users as $user)
{
var_dump($user->name);
}

Retrieve a single row from the table

$user = DB::table('users')->where('name', 'John')->first();
var_dump($user->name);

Retrieve rows for a single column

$name = DB::table('users')->where('name', 'John')->pluck('name');

Retrieve a list of column values

$roles = DB::table('roles')->lists('title');

This method will return the function of an array header. You can also specify a custom key column to return the array

$roles = DB::table('roles')->lists('title', 'name');

Specify a Select clause

$users = DB::table('users')->select('name', 'email')->get();
　$users = DB::table('users')->distinct()->get();
　$users = DB::table('users')->select('name as user_name')->get();

Select clause is added to a Existing query $query = DB::table('users')->select('name');

$users = $query->addSelect('age')->get();

where

$users = DB::table('users')->where('votes', '>', 100)->get();

OR

$users = DB::table('users')->where('votes', '>', 100)->orWhere('name', 'John')->get();

Where Between

$users = DB::table('users')->whereBetween('votes', array(1, 100))->get();

Where Not Between

$users = DB::table('users')->whereNotBetween('votes', array(1, 100))->get();

Where In With An Array

$users = DB::table('users')->whereIn('id', array(1, 2, 3))->get();
$users = DB::table('users')->whereNotIn('id', array(1, 2, 3))->get();

Using Where Null To Find Records With Unset Values

$users = DB::table('users')->whereNull('updated_at')->get();

Order By, Group By, And Having

$users = DB::table('users')->orderBy('name', 'desc')->groupBy('count')->having('count', '>', 100)->get();

Offset & Limit

$users = DB::table('users')->skip(10)->take(5)->get();

2. Connection

Joins

The query builder can also be used to write join statements. Take a look at the following example:

Basic Join Statement

DB::table('users')
　　->join('contacts', 'users.id', '=', 'contacts.user_id')
　　->join('orders', 'users.id', '=', 'orders.user_id')
　　->select('users.id', 'contacts.phone', 'orders.price')
　　->get();

Left join statement

DB::table('users')
　　->leftJoin('posts', 'users.id', '=', 'posts.user_id')
　　->get();
　　DB::table('users')
　　->join('contacts', function($join)
　　{
　　$join->on('users.id', '=', 'contacts.user_id')->orOn(...);
　　})
　　->get();
　　DB::table('users')
　　->join('contacts', function($join)
　　{
　　$join->on('users.id', '=', 'contacts.user_id')
　　->where('contacts.user_id', '>', 5);
　　})
　　->get();

3. Grouping

Sometimes, you may need to create more advanced where clauses, such as "exists" or nested parameter groupings. The Laravel query builder can handle these: DB::table('users')

->where('name', '=', 'John')
->orWhere(function($query)
{
$query->where('votes', '>', 100)
->where('title', '<>', 'Admin');
})
->get();

The above query will produce the following SQL:

select * from users where name = 'John' or (votes > 100 and title 
<> 'Admin')
　　Exists Statements
　　DB::table('users')
　　->whereExists(function($query)
　　{
　　$query->select(DB::raw(1))
　　->from('orders')
　　->whereRaw('orders.user_id = users.id');
　　})
　　->get();

The above query will produce the following SQL:

select * from userswhere exists (
select 1 from orders where orders.user_id = users.id
)

4. Aggregation

The query builder also provides various aggregation methods, such as statistics, max, min, avg and sum.

Using Aggregate Methods

$users = DB::table('users')->count();
$price = DB::table('orders')->max('price');
$price = DB::table('orders')->min('price');
$price = DB::table('orders')->avg('price');
$total = DB::table('users')->sum('votes');

Raw Expressions

Sometimes you may need to use a raw expression query. These expressions will be injected into the query string, so be careful not to create any SQL injection points! To create a raw expression, you can use DB:rawmethod:

Using A Raw Expression

$users = DB::table('users')
->select(DB::raw('count(*) as user_count, status'))
->where('status', '<>', 1)
->groupBy('status')
->get();

Increment or decrement the value of a column

DB::table('users')->increment('votes');
DB::table('users')->increment('votes', 5);
DB::table('users')->decrement('votes');
DB::table('users')->decrement('votes', 5);

You can also specify additional column updates:

DB::table('users')->increment('votes', 1, array('name' => 'John'));

Inserts

Insert records into the table

DB::table('users')->insert(
array('email' => 'john@example.com', 'votes' => 0)
);

Insert records into the table with automatically incremented ID

If the table has an automatically incremented id field Use insertGetId to insert a record and retrieve the id:

$id = DB::table('users')->insertGetId(
array('email' => 'john@example.com', 'votes' => 0)
);

Note: When using the PostgreSQL insertGetId method it is expected that the auto-incrementing column will be named "id".

Insert multiple records into the table

DB::table('users')->insert(array(
array('email' => 'taylor@example.com', 'votes' => 0),
array('email' => 'dayle@example.com', 'votes' => 0),
));

4. Updates

Update records in a table

DB::table('users')
->where('id', 1)
->update(array('votes' => 1));

5. Deletes

Delete records in the table

DB::table('users')->where('votes', '<', 100)->delete();

Delete all records in the table

DB::table('users')->delete();

Delete a table

DB::table('users')->truncate();

6. Unions

The query builder also provides a quick way to " Union" two queries:

$first = DB::table('users')->whereNull('first_name');
　　$users = 
DB::table('users')->whereNull('last_name')->union($first)->get();

The unionAll method is also available and has the same method signature.

　Pessimistic Locking

The query builder includes some "pessimistic locking" features to help you with your SELECT statements. To run the SELECT statement "shared lock", you can use the sharedLock method to query:

DB::table('users')->where('votes', '>', 
100)->sharedLock()->get();

To update "lock" in a SELECT statement, you can use the lockForUpdate method to query:

DB::table('users')->where('votes', '>', 100)->lockForUpdate()->get();

7. Caching queries

You can easily cache the results of a query using mnemonics:

$users = DB::table('users')->remember(10)->get();

In this example, the results of the query will be cached for ten minutes. When query results are cached, they are not run against the database and the results will be loaded from the default cache driver specified by your application. If you are using a driver that supports caching, you can also add tags to cache:

$users = DB::table('users')->cacheTags(array('people', 'authors'))->remember(10)->get();

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