- Introduction
- Running Database Queries
- Select Statements
- Raw Expressions
- Joins
- Unions
- Basic Where Clauses
- Advanced Where Clauses
- Ordering, Grouping, Limit & Offset
- Conditional Clauses
- Insert Statements
- Update Statements
- Delete Statements
- Pessimistic Locking
- Debugging
Laravel's database query builder provides a convenient, fluent interface to creating and running database queries. It can be used to perform most database operations in your application and works perfectly with all of Laravel's supported database systems.
The Laravel query builder uses PDO parameter binding to protect your application against SQL injection attacks. There is no need to clean or sanitize strings passed to the query builder as query bindings.
{note} PDO does not support binding column names. Therefore, you should never allow user input to dictate the column names referenced by your queries, including "order by" columns.
You may use the table
method provided by the DB
facade to begin a query. The table
method returns a fluent query builder instance for the given table, allowing you to chain more constraints onto the query and then finally retrieve the results of the query using the get
method:
<?php
namespace App\Http\Controllers;
use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\DB;
class UserController extends Controller
{
/**
* Show a list of all of the application's users.
*
* @return \Illuminate\Http\Response
*/
public function index()
{
$users = DB::table('users')->get();
return view('user.index', ['users' => $users]);
}
}
The get
method returns an Illuminate\Support\Collection
instance containing the results of the query where each result is an instance of the PHP stdClass
object. You may access each column's value by accessing the column as a property of the object:
use Illuminate\Support\Facades\DB;
$users = DB::table('users')->get();
foreach ($users as $user) {
echo $user->name;
}
{tip} Laravel collections provide a variety of extremely powerful methods for mapping and reducing data. For more information on Laravel collections, check out the collection documentation.
If you just need to retrieve a single row from a database table, you may use the DB
facade's first
method. This method will return a single stdClass
object:
$user = DB::table('users')->where('name', 'John')->first();
return $user->email;
If you don't need an entire row, you may extract a single value from a record using the value
method. This method will return the value of the column directly:
$email = DB::table('users')->where('name', 'John')->value('email');
To retrieve a single row by its id
column value, use the find
method:
$user = DB::table('users')->find(3);
If you would like to retrieve an Illuminate\Support\Collection
instance containing the values of a single column, you may use the pluck
method. In this example, we'll retrieve a collection of user titles:
use Illuminate\Support\Facades\DB;
$titles = DB::table('users')->pluck('title');
foreach ($titles as $title) {
echo $title;
}
You may specify the column that the resulting collection should use as its keys by providing a second argument to the pluck
method:
$titles = DB::table('users')->pluck('title', 'name');
foreach ($titles as $name => $title) {
echo $title;
}
If you need to work with thousands of database records, consider using the chunk
method provided by the DB
facade. This method retrieves a small chunk of results at a time and feeds each chunk into a closure for processing. For example, let's retrieve the entire users
table in chunks of 100 records at a time:
use Illuminate\Support\Facades\DB;
DB::table('users')->orderBy('id')->chunk(100, function ($users) {
foreach ($users as $user) {
//
}
});
You may stop further chunks from being processed by returning false
from the closure:
DB::table('users')->orderBy('id')->chunk(100, function ($users) {
// Process the records...
return false;
});
If you are updating database records while chunking results, your chunk results could change in unexpected ways. If you plan to update the retrieved records while chunking, it is always best to use the chunkById
method instead. This method will automatically paginate the results based on the record's primary key:
DB::table('users')->where('active', false)
->chunkById(100, function ($users) {
foreach ($users as $user) {
DB::table('users')
->where('id', $user->id)
->update(['active' => true]);
}
});
{note} When updating or deleting records inside the chunk callback, any changes to the primary key or foreign keys could affect the chunk query. This could potentially result in records not being included in the chunked results.
The lazy
method works similarly to the chunk
method in the sense that it executes the query in chunks. However, instead of passing each chunk into a callback, the lazy()
method returns a LazyCollection
, which lets you interact with the results as a single stream:
use Illuminate\Support\Facades\DB;
DB::table('users')->orderBy('id')->lazy()->each(function ($user) {
//
});
Once again, if you plan to update the retrieved records while iterating over them, it is best to use the lazyById
or lazyByIdDesc
methods instead. These methods will automatically paginate the results based on the record's primary key:
DB::table('users')->where('active', false)
->lazyById()->each(function ($user) {
DB::table('users')
->where('id', $user->id)
->update(['active' => true]);
});
{note} When updating or deleting records while iterating over them, any changes to the primary key or foreign keys could affect the chunk query. This could potentially result in records not being included in the results.
The query builder also provides a variety of methods for retrieving aggregate values like count
, max
, min
, avg
, and sum
. You may call any of these methods after constructing your query:
use Illuminate\Support\Facades\DB;
$users = DB::table('users')->count();
$price = DB::table('orders')->max('price');
Of course, you may combine these methods with other clauses to fine-tune how your aggregate value is calculated:
$price = DB::table('orders')
->where('finalized', 1)
->avg('price');
Instead of using the count
method to determine if any records exist that match your query's constraints, you may use the exists
and doesntExist
methods:
if (DB::table('orders')->where('finalized', 1)->exists()) {
// ...
}
if (DB::table('orders')->where('finalized', 1)->doesntExist()) {
// ...
}
You may not always want to select all columns from a database table. Using the select
method, you can specify a custom "select" clause for the query:
use Illuminate\Support\Facades\DB;
$users = DB::table('users')
->select('name', 'email as user_email')
->get();
The distinct
method allows you to force the query to return distinct results:
$users = DB::table('users')->distinct()->get();
If you already have a query builder instance and you wish to add a column to its existing select clause, you may use the addSelect
method:
$query = DB::table('users')->select('name');
$users = $query->addSelect('age')->get();
Sometimes you may need to insert an arbitrary string into a query. To create a raw string expression, you may use the raw
method provided by the DB
facade:
$users = DB::table('users')
->select(DB::raw('count(*) as user_count, status'))
->where('status', '<>', 1)
->groupBy('status')
->get();
{note} Raw statements will be injected into the query as strings, so you should be extremely careful to avoid creating SQL injection vulnerabilities.
Instead of using the DB::raw
method, you may also use the following methods to insert a raw expression into various parts of your query. Remember, Laravel can not guarantee that any query using raw expressions is protected against SQL injection vulnerabilities.
The selectRaw
method can be used in place of addSelect(DB::raw(...))
. This method accepts an optional array of bindings as its second argument:
$orders = DB::table('orders')
->selectRaw('price * ? as price_with_tax', [1.0825])
->get();
The whereRaw
and orWhereRaw
methods can be used to inject a raw "where" clause into your query. These methods accept an optional array of bindings as their second argument:
$orders = DB::table('orders')
->whereRaw('price > IF(state = "TX", ?, 100)', [200])
->get();
The havingRaw
and orHavingRaw
methods may be used to provide a raw string as the value of the "having" clause. These methods accept an optional array of bindings as their second argument:
$orders = DB::table('orders')
->select('department', DB::raw('SUM(price) as total_sales'))
->groupBy('department')
->havingRaw('SUM(price) > ?', [2500])
->get();
The orderByRaw
method may be used to provide a raw string as the value of the "order by" clause:
$orders = DB::table('orders')
->orderByRaw('updated_at - created_at DESC')
->get();
The groupByRaw
method may be used to provide a raw string as the value of the group by
clause:
$orders = DB::table('orders')
->select('city', 'state')
->groupByRaw('city, state')
->get();
The query builder may also be used to add join clauses to your queries. To perform a basic "inner join", you may use the join
method on a query builder instance. The first argument passed to the join
method is the name of the table you need to join to, while the remaining arguments specify the column constraints for the join. You may even join multiple tables in a single query:
use Illuminate\Support\Facades\DB;
$users = DB::table('users')
->join('contacts', 'users.id', '=', 'contacts.user_id')
->join('orders', 'users.id', '=', 'orders.user_id')
->select('users.*', 'contacts.phone', 'orders.price')
->get();
If you would like to perform a "left join" or "right join" instead of an "inner join", use the leftJoin
or rightJoin
methods. These methods have the same signature as the join
method:
$users = DB::table('users')
->leftJoin('posts', 'users.id', '=', 'posts.user_id')
->get();
$users = DB::table('users')
->rightJoin('posts', 'users.id', '=', 'posts.user_id')
->get();
You may use the crossJoin
method to perform a "cross join". Cross joins generate a cartesian product between the first table and the joined table:
$sizes = DB::table('sizes')
->crossJoin('colors')
->get();
You may also specify more advanced join clauses. To get started, pass a closure as the second argument to the join
method. The closure will receive a Illuminate\Database\Query\JoinClause
instance which allows you to specify constraints on the "join" clause:
DB::table('users')
->join('contacts', function ($join) {
$join->on('users.id', '=', 'contacts.user_id')->orOn(...);
})
->get();
If you would like to use a "where" clause on your joins, you may use the where
and orWhere
methods provided by the JoinClause
instance. Instead of comparing two columns, these methods will compare the column against a value:
DB::table('users')
->join('contacts', function ($join) {
$join->on('users.id', '=', 'contacts.user_id')
->where('contacts.user_id', '>', 5);
})
->get();
You may use the joinSub
, leftJoinSub
, and rightJoinSub
methods to join a query to a subquery. Each of these methods receives three arguments: the subquery, its table alias, and a closure that defines the related columns. In this example, we will retrieve a collection of users where each user record also contains the created_at
timestamp of the user's most recently published blog post:
$latestPosts = DB::table('posts')
->select('user_id', DB::raw('MAX(created_at) as last_post_created_at'))
->where('is_published', true)
->groupBy('user_id');
$users = DB::table('users')
->joinSub($latestPosts, 'latest_posts', function ($join) {
$join->on('users.id', '=', 'latest_posts.user_id');
})->get();
The query builder also provides a convenient method to "union" two or more queries together. For example, you may create an initial query and use the union
method to union it with more queries:
use Illuminate\Support\Facades\DB;
$first = DB::table('users')
->whereNull('first_name');
$users = DB::table('users')
->whereNull('last_name')
->union($first)
->get();
In addition to the union
method, the query builder provides a unionAll
method. Queries that are combined using the unionAll
method will not have their duplicate results removed. The unionAll
method has the same method signature as the union
method.
You may use the query builder's where
method to add "where" clauses to the query. The most basic call to the where
method requires three arguments. The first argument is the name of the column. The second argument is an operator, which can be any of the database's supported operators. The third argument is the value to compare against the column's value.
For example, the following query retrieves users where the value of the votes
column is equal to 100
and the value of the age
column is greater than 35
:
$users = DB::table('users')
->where('votes', '=', 100)
->where('age', '>', 35)
->get();
For convenience, if you want to verify that a column is =
to a given value, you may pass the value as the second argument to the where
method. Laravel will assume you would like to use the =
operator:
$users = DB::table('users')->where('votes', 100)->get();
As previously mentioned, you may use any operator that is supported by your database system:
$users = DB::table('users')
->where('votes', '>=', 100)
->get();
$users = DB::table('users')
->where('votes', '<>', 100)
->get();
$users = DB::table('users')
->where('name', 'like', 'T%')
->get();
You may also pass an array of conditions to the where
function. Each element of the array should be an array containing the three arguments typically passed to the where
method:
$users = DB::table('users')->where([
['status', '=', '1'],
['subscribed', '<>', '1'],
])->get();
{note} PDO does not support binding column names. Therefore, you should never allow user input to dictate the column names referenced by your queries, including "order by" columns.
When chaining together calls to the query builder's where
method, the "where" clauses will be joined together using the and
operator. However, you may use the orWhere
method to join a clause to the query using the or
operator. The orWhere
method accepts the same arguments as the where
method:
$users = DB::table('users')
->where('votes', '>', 100)
->orWhere('name', 'John')
->get();
If you need to group an "or" condition within parentheses, you may pass a closure as the first argument to the orWhere
method:
$users = DB::table('users')
->where('votes', '>', 100)
->orWhere(function($query) {
$query->where('name', 'Abigail')
->where('votes', '>', 50);
})
->get();
The example above will produce the following SQL:
select * from users where votes > 100 or (name = 'Abigail' and votes > 50)
{note} You should always group
orWhere
calls in order to avoid unexpected behavior when global scopes are applied.
Laravel also supports querying JSON column types on databases that provide support for JSON column types. Currently, this includes MySQL 5.7+, PostgreSQL, SQL Server 2016, and SQLite 3.9.0 (with the JSON1 extension). To query a JSON column, use the ->
operator:
$users = DB::table('users')
->where('preferences->dining->meal', 'salad')
->get();
You may use whereJsonContains
to query JSON arrays. This feature is not supported by the SQLite database:
$users = DB::table('users')
->whereJsonContains('options->languages', 'en')
->get();
If your application uses the MySQL or PostgreSQL databases, you may pass an array of values to the whereJsonContains
method:
$users = DB::table('users')
->whereJsonContains('options->languages', ['en', 'de'])
->get();
You may use whereJsonLength
method to query JSON arrays by their length:
$users = DB::table('users')
->whereJsonLength('options->languages', 0)
->get();
$users = DB::table('users')
->whereJsonLength('options->languages', '>', 1)
->get();
whereBetween / orWhereBetween
The whereBetween
method verifies that a column's value is between two values:
$users = DB::table('users')
->whereBetween('votes', [1, 100])
->get();
whereNotBetween / orWhereNotBetween
The whereNotBetween
method verifies that a column's value lies outside of two values:
$users = DB::table('users')
->whereNotBetween('votes', [1, 100])
->get();
whereIn / whereNotIn / orWhereIn / orWhereNotIn
The whereIn
method verifies that a given column's value is contained within the given array:
$users = DB::table('users')
->whereIn('id', [1, 2, 3])
->get();
The whereNotIn
method verifies that the given column's value is not contained in the given array:
$users = DB::table('users')
->whereNotIn('id', [1, 2, 3])
->get();
{note} If you are adding a large array of integer bindings to your query, the
whereIntegerInRaw
orwhereIntegerNotInRaw
methods may be used to greatly reduce your memory usage.
whereNull / whereNotNull / orWhereNull / orWhereNotNull
The whereNull
method verifies that the value of the given column is NULL
:
$users = DB::table('users')
->whereNull('updated_at')
->get();
The whereNotNull
method verifies that the column's value is not NULL
:
$users = DB::table('users')
->whereNotNull('updated_at')
->get();
whereDate / whereMonth / whereDay / whereYear / whereTime
The whereDate
method may be used to compare a column's value against a date:
$users = DB::table('users')
->whereDate('created_at', '2016-12-31')
->get();
The whereMonth
method may be used to compare a column's value against a specific month:
$users = DB::table('users')
->whereMonth('created_at', '12')
->get();
The whereDay
method may be used to compare a column's value against a specific day of the month:
$users = DB::table('users')
->whereDay('created_at', '31')
->get();
The whereYear
method may be used to compare a column's value against a specific year:
$users = DB::table('users')
->whereYear('created_at', '2016')
->get();
The whereTime
method may be used to compare a column's value against a specific time:
$users = DB::table('users')
->whereTime('created_at', '=', '11:20:45')
->get();
whereColumn / orWhereColumn
The whereColumn
method may be used to verify that two columns are equal:
$users = DB::table('users')
->whereColumn('first_name', 'last_name')
->get();
You may also pass a comparison operator to the whereColumn
method:
$users = DB::table('users')
->whereColumn('updated_at', '>', 'created_at')
->get();
You may also pass an array of column comparisons to the whereColumn
method. These conditions will be joined using the and
operator:
$users = DB::table('users')
->whereColumn([
['first_name', '=', 'last_name'],
['updated_at', '>', 'created_at'],
])->get();
Sometimes you may need to group several "where" clauses within parentheses in order to achieve your query's desired logical grouping. In fact, you should generally always group calls to the orWhere
method in parentheses in order to avoid unexpected query behavior. To accomplish this, you may pass a closure to the where
method:
$users = DB::table('users')
->where('name', '=', 'John')
->where(function ($query) {
$query->where('votes', '>', 100)
->orWhere('title', '=', 'Admin');
})
->get();
As you can see, passing a closure into the where
method instructs the query builder to begin a constraint group. The closure will receive a query builder instance which you can use to set the constraints that should be contained within the parenthesis group. The example above will produce the following SQL:
select * from users where name = 'John' and (votes > 100 or title = 'Admin')
{note} You should always group
orWhere
calls in order to avoid unexpected behavior when global scopes are applied.
The whereExists
method allows you to write "where exists" SQL clauses. The whereExists
method accepts a closure which will receive a query builder instance, allowing you to define the query that should be placed inside of the "exists" clause:
$users = DB::table('users')
->whereExists(function ($query) {
$query->select(DB::raw(1))
->from('orders')
->whereColumn('orders.user_id', 'users.id');
})
->get();
The query above will produce the following SQL:
select * from users
where exists (
select 1
from orders
where orders.user_id = users.id
)
Sometimes you may need to construct a "where" clause that compares the results of a subquery to a given value. You may accomplish this by passing a closure and a value to the where
method. For example, the following query will retrieve all users who have a recent "membership" of a given type;
use App\Models\User;
$users = User::where(function ($query) {
$query->select('type')
->from('membership')
->whereColumn('membership.user_id', 'users.id')
->orderByDesc('membership.start_date')
->limit(1);
}, 'Pro')->get();
Or, you may need to construct a "where" clause that compares a column to the results of a subquery. You may accomplish this by passing a column, operator, and closure to the where
method. For example, the following query will retrieve all income records where the amount is less than average;
use App\Models\Income;
$incomes = Income::where('amount', '<', function ($query) {
$query->selectRaw('avg(i.amount)')->from('incomes as i');
})->get();
The orderBy
method allows you to sort the results of the query by a given column. The first argument accepted by the orderBy
method should be the column you wish to sort by, while the second argument determines the direction of the sort and may be either asc
or desc
:
$users = DB::table('users')
->orderBy('name', 'desc')
->get();
To sort by multiple columns, you may simply invoke orderBy
as many times as necessary:
$users = DB::table('users')
->orderBy('name', 'desc')
->orderBy('email', 'asc')
->get();
The latest
and oldest
methods allow you to easily order results by date. By default, the result will be ordered by the table's created_at
column. Or, you may pass the column name that you wish to sort by:
$user = DB::table('users')
->latest()
->first();
The inRandomOrder
method may be used to sort the query results randomly. For example, you may use this method to fetch a random user:
$randomUser = DB::table('users')
->inRandomOrder()
->first();
The reorder
method removes all of the "order by" clauses that have previously been applied to the query:
$query = DB::table('users')->orderBy('name');
$unorderedUsers = $query->reorder()->get();
You may pass a column and direction when calling the reorder
method in order to remove all existing "order by" clauses and apply an entirely new order to the query:
$query = DB::table('users')->orderBy('name');
$usersOrderedByEmail = $query->reorder('email', 'desc')->get();
As you might expect, the groupBy
and having
methods may be used to group the query results. The having
method's signature is similar to that of the where
method:
$users = DB::table('users')
->groupBy('account_id')
->having('account_id', '>', 100)
->get();
You can use the havingBetween
method to filter the results within a given range:
$report = DB::table('orders')
->selectRaw('count(id) as number_of_orders, customer_id')
->groupBy('customer_id')
->havingBetween('number_of_orders', [5, 15])
->get();
You may pass multiple arguments to the groupBy
method to group by multiple columns:
$users = DB::table('users')
->groupBy('first_name', 'status')
->having('account_id', '>', 100)
->get();
To build more advanced having
statements, see the havingRaw
method.
You may use the skip
and take
methods to limit the number of results returned from the query or to skip a given number of results in the query:
$users = DB::table('users')->skip(10)->take(5)->get();
Alternatively, you may use the limit
and offset
methods. These methods are functionally equivalent to the take
and skip
methods, respectively:
$users = DB::table('users')
->offset(10)
->limit(5)
->get();
Sometimes you may want certain query clauses to apply to a query based on another condition. For instance, you may only want to apply a where
statement if a given input value is present on the incoming HTTP request. You may accomplish this using the when
method:
$role = $request->input('role');
$users = DB::table('users')
->when($role, function ($query, $role) {
return $query->where('role_id', $role);
})
->get();
The when
method only executes the given closure when the first argument is true
. If the first argument is false
, the closure will not be executed. So, in the example above, the closure given to the when
method will only be invoked if the role
field is present on the incoming request and evaluates to true
.
You may pass another closure as the third argument to the when
method. This closure will only execute if the first argument evaluates as false
. To illustrate how this feature may be used, we will use it to configure the default ordering of a query:
$sortByVotes = $request->input('sort_by_votes');
$users = DB::table('users')
->when($sortByVotes, function ($query, $sortByVotes) {
return $query->orderBy('votes');
}, function ($query) {
return $query->orderBy('name');
})
->get();
The query builder also provides an insert
method that may be used to insert records into the database table. The insert
method accepts an array of column names and values:
DB::table('users')->insert([
'email' => '[email protected]',
'votes' => 0
]);
You may insert several records at once by passing an array of arrays. Each array represents a record that should be inserted into the table:
DB::table('users')->insert([
['email' => '[email protected]', 'votes' => 0],
['email' => '[email protected]', 'votes' => 0],
]);
The insertOrIgnore
method will ignore errors while inserting records into the database:
DB::table('users')->insertOrIgnore([
['id' => 1, 'email' => '[email protected]'],
['id' => 2, 'email' => '[email protected]'],
]);
{note}
insertOrIgnore
will ignore duplicate records and also may ignore other types of errors depending on the database engine. For example,insertOrIgnore
will bypass MySQL's strict mode.
If the table has an auto-incrementing id, use the insertGetId
method to insert a record and then retrieve the ID:
$id = DB::table('users')->insertGetId(
['email' => '[email protected]', 'votes' => 0]
);
{note} When using PostgreSQL the
insertGetId
method expects the auto-incrementing column to be namedid
. If you would like to retrieve the ID from a different "sequence", you may pass the column name as the second parameter to theinsertGetId
method.
The upsert
method will insert records that do not exist and update the records that already exist with new values that you may specify. The method's first argument consists of the values to insert or update, while the second argument lists the column(s) that uniquely identify records within the associated table. The method's third and final argument is an array of columns that should be updated if a matching record already exists in the database:
DB::table('flights')->upsert([
['departure' => 'Oakland', 'destination' => 'San Diego', 'price' => 99],
['departure' => 'Chicago', 'destination' => 'New York', 'price' => 150]
], ['departure', 'destination'], ['price']);
In the example above, Laravel will attempt to insert two records. If a record already exists with the same departure
and destination
column values, Laravel will update that record's price
column.
{note} All databases except SQL Server require the columns in the second argument of the
upsert
method to have a "primary" or "unique" index. In addition, the MySQL database driver ignores the second argument of theupsert
method and always uses the "primary" and "unique" indexes of the table to detect existing records.
In addition to inserting records into the database, the query builder can also update existing records using the update
method. The update
method, like the insert
method, accepts an array of column and value pairs indicating the columns to be updated. The update
method returns the number of affected rows. You may constrain the update
query using where
clauses:
$affected = DB::table('users')
->where('id', 1)
->update(['votes' => 1]);
Sometimes you may want to update an existing record in the database or create it if no matching record exists. In this scenario, the updateOrInsert
method may be used. The updateOrInsert
method accepts two arguments: an array of conditions by which to find the record, and an array of column and value pairs indicating the columns to be updated.
The updateOrInsert
method will attempt to locate a matching database record using the first argument's column and value pairs. If the record exists, it will be updated with the values in the second argument. If the record can not be found, a new record will be inserted with the merged attributes of both arguments:
DB::table('users')
->updateOrInsert(
['email' => '[email protected]', 'name' => 'John'],
['votes' => '2']
);
When updating a JSON column, you should use ->
syntax to update the appropriate key in the JSON object. This operation is supported on MySQL 5.7+ and PostgreSQL 9.5+:
$affected = DB::table('users')
->where('id', 1)
->update(['options->enabled' => true]);
The query builder also provides convenient methods for incrementing or decrementing the value of a given column. Both of these methods accept at least one argument: the column to modify. A second argument may be provided to specify the amount by which the column should be incremented or decremented:
DB::table('users')->increment('votes');
DB::table('users')->increment('votes', 5);
DB::table('users')->decrement('votes');
DB::table('users')->decrement('votes', 5);
You may also specify additional columns to update during the operation:
DB::table('users')->increment('votes', 1, ['name' => 'John']);
The query builder's delete
method may be used to delete records from the table. You may constrain delete
statements by adding "where" clauses before calling the delete
method:
DB::table('users')->delete();
DB::table('users')->where('votes', '>', 100)->delete();
If you wish to truncate an entire table, which will remove all records from the table and reset the auto-incrementing ID to zero, you may use the truncate
method:
DB::table('users')->truncate();
When truncating a PostgreSQL database, the CASCADE
behavior will be applied. This means that all foreign key related records in other tables will be deleted as well.
The query builder also includes a few functions to help you achieve "pessimistic locking" when executing your select
statements. To execute a statement with a "shared lock", you may call the sharedLock
method. A shared lock prevents the selected rows from being modified until your transaction is committed:
DB::table('users')
->where('votes', '>', 100)
->sharedLock()
->get();
Alternatively, you may use the lockForUpdate
method. A "for update" lock prevents the selected records from being modified or from being selected with another shared lock:
DB::table('users')
->where('votes', '>', 100)
->lockForUpdate()
->get();
You may use the dd
and dump
methods while building a query to dump the current query bindings and SQL. The dd
method will display the debug information and then stop executing the request. The dump
method will display the debug information but allow the request to continue executing:
DB::table('users')->where('votes', '>', 100)->dd();
DB::table('users')->where('votes', '>', 100)->dump();