Laravel PHP Web Development Framework

Last Update:2016-07-14 Source: Internet

Author: User

Tags php web development

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Laravel is a simple, elegant PHP Web development Framework (php Web framework). It frees you from the messy code of noodles, and it helps you build a perfect web app, and every line of code can be concise and Expressive.This article explains the Laravel framework of database curd operation, coherent operation, the use of chain operation, including a large number of database operations commonly used methods, interested students reference.Laravel is a simple, elegant PHP Web development Framework (php Web framework). It frees you from the messy code of noodles, and it helps you build a perfect web app, and every line of code can be concise and Expressive.first, SelectsRetrieving all rows in a tableThe code is as Follows: $users = db::table (' users ')->get (); foreach ($users as $user) { Var_dump ($user->name); }Retrieving a single row from a tableThe code is as Follows: $user = db::table (' users ')->where (' name ', ' John ')->first (); Var_dump ($user->name); Retrieving rows for a single columnThe code is as Follows: $name = db::table (' users ')->where (' name ', ' John ')->pluck (' name '); Retrieving a list of column valuesThe code is as Follows: $roles = db::table (' roles ')->lists (' title '); The method returns the function of an array header. You can also specify a custom key column to return an array ofThe code is as Follows: $roles = db::table (' roles ')->lists (' title ', ' name '); Specify a SELECT clauseThe code is as Follows: $users = db::table (' users ')->select (' name ', ' email ')->get (); $users = db::table (' users ')->distinct ()->get (); $users = db::table (' users ')->select (' name as user_name ')->get ();The SELECT clause is added to an existing query $query = db::table (' users ')->select (' name ');The code is as Follows: $users = $query->addselect (' Age ')->get ();whereThe code is as Follows: $users = db::table (' users ')->where (' votes ', ' > ', +)->get ();ORThe code is as Follows: $users = db::table (' users ')->where (' votes ', ' > ', ')->orwhere (' name ', ' John ')->get ();Where betweenThe code is as Follows: $users = db::table (' users ')->wherebetween (' votes ', Array (1))->get ();Where not betweenThe code is as Follows: $users = db::table (' users ')->wherenotbetween (' votes ', Array (1))->get ();Where in with an ArrayThe code is as Follows: $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 ValuesThe code is as Follows: $users = db::table (' users ')->wherenull (' updated_at ')->get ();Order by, Group by, and haveThe code is as Follows: $users = db::table (' users ')->orderby (' name ', ' desc ')->groupby (' count ')->having (' count ', ' > ', Get ();Offset & LimitThe code is as Follows: $users = db::table (' users ')->skip (ten)->take (5)->get ();second, the connectionJoinsThe query Builder can also be used to write connection Statements. Take a look at the following example:Basic Join StatementThe code is as Follows: Db::table (' Users ') ->join (' contacts ', ' users.id ', ' = ', ' contacts.user_id ') ->join (' orders ', ' users.id ', ' = ', ' orders.user_id ') ->select (' users.id ', ' contacts.phone ', ' Orders.price ') ->get ();Left join-up statementsThe code is as Follows: Db::table (' Users ') ->leftjoin (' posts ', ' users.id ', ' = ', ' posts.user_id ') ->get (); Db::table (' Users ') ->join (' contacts ', function ($join) { $join->on (' users.id ', ' = ', ' contacts.user_id ')->oron (...); }) ->get (); Db::table (' Users ') ->join (' contacts ', function ($join) { $join->on (' users.id ', ' = ', ' contacts.user_id ') ->where (' contacts.user_id ', ' > ', 5); }) ->get ();third, Groupsometimes, you may want to create more advanced where clauses, such as "presence" or nested parameter groupings. Laravel Query Builder can handle these:The code is as Follows: Db::table (' Users ') ->where (' name ', ' = ', ' John ') ->orwhere (function ($query) { $query->where (' votes ', ' > ', 100) ->where (' title ', ' <> ', ' Admin '); }) ->get (); The above query will produce the following sql:The code is as Follows: SELECT * from users where name = ' John ' or (votes > and title <> ' Admin ') Exists statements Db::table (' Users ') ->whereexists (function ($query) { $query->select (db::raw (1)) ->from (' orders ') ->whereraw (' orders.user_id = users.id '); }) ->get ();The above query will produce the following sql:The code is as Follows: SELECT * FROM Userswhere exists ( Select 1 from orders where orders.user_id = Users.id )Iv. AggregationThe Query Builder also provides a variety of aggregation methods, such as statistics, max, min,avg, and Sum.Using Aggregate MethodsThe code is as Follows: $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 ExpressionsSometimes you may want to use a query with a raw Expression. These expressions will inject the query string, so be careful not to create any SQL injection points! to create a primitive expression, you can use Db:rawmethod:Using A Raw ExpressionThe code is as Follows: $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 columnThe code is as Follows: 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:The code is as Follows: Db::table (' Users ')->increment (' votes ', 1, array (' name ' = ' John ') ');InsertsInserting records into a tableThe code is as Follows: db::table (' users ')->insert ( array (' Email ' = ' [email protected] ', ' votes ' + 0) );Automatically increment the ID of the record into the tableIf the table has an auto-incrementing ID field, use Insertgetid to insert a record and retrieve the Id:The code is as Follows: $id = db::table (' users ')->insertgetid ( array (' Email ' = ' [email protected] ', ' votes ' + 0) );Note: when using the PostgreSQL Insertgetid method, It is expected that the Self-increment column is named "id".Inserting multiple records into a tableThe code is as Follows: Db::table (' users ')->insert (array ( Array (' Email ' = ' [email protected] ', ' votes ' + 0), Array (' Email ' = ' [email protected] ', ' votes ' + 0), ));Iv. UpdatesTo update a record in a tableThe code is as Follows: db::table (' users ') ->where (' ID ', 1) ->update (array (' votes ' = 1));wu, DeletesDelete a record in a tableThe code is as Follows: db::table (' Users ')->where (' votes ', ' < ', +)->delete ();Delete all records in a tableThe code is as Follows: Db::table (' users ')->delete (); Delete a tableThe code is as Follows: Db::table (' users ')->truncate ();liu, UnionsThe Query Builder also provides a quick way to "federate" two of queries:The code is as Follows: $first = db::table (' users ')->wherenull (' first_name '); $users = Db::table (' users ')->wherenull (' last_name ')->union ($first)->get ();The UnionAll method can also have the same method Signature.Pessimistic LockingThe query Builder includes some "pessimistic locking" features to help you make your select Statement. Run the SELECT statement "shared lock", which you can query using the Sharedlock method:The code is as Follows: Db::table (' Users ')->where (' votes ', ' > ', ()->sharedlock ()->get (); Update "lock" in a select statement, you can use the Lockforupdate method to Query:The code is as Follows: Db::table (' Users ')->where (' votes ', ' > ', ')->lockforupdate ()->get ();seven, Cache QueryYou can easily cache the results of a query using the mnemonic method:The code is as Follows: $users = db::table (' users ')->remember (ten)->get (); In this case, the result of the query will be cached for 10 minutes .　　When you query the results cache, the database is not run, and the results are assigned to your application from the default cache load Driver. If you are using a driver that supports caching, you can also add a tag to cache:The code is as Follows: $users = db::table (' users ')->cachetags (array (' people ', ' authors '))->remember ()->get ();Laravel PHP Web Development Framework

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