PHP Development Framework Laravel Database Operation method Summary, Framework laravel_php Tutorial

PHP Development Framework Laravel Database Operation method Summary, framework Laravel

One, read/write connection

Sometimes you might want to use a database connection for a SELECT statement, and another for inserting, updating, and deleting statements. Laravel makes this breeze, will always use the correct connection whether using the original query, query Builder or eloquent ORM.

How the read/write connection should be configured, let's take a look at this example:
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' MySQL ' = array (' read ' + = Array (' host ' = ' 192.168.1.1 '), ' write ' = = Array (' host ' = ' 196.168.1.2 '), ' Driver ' + ' mysql ', ' database ' = ' database ', ' username ' + ' root ', ' password ' + ', ' charset ' = ' utf8 ', ' Collation ' = ' utf8_unicode_ci ', ' prefix ' and ' = ')

Note that two keys are added to the configuration array: Read and write. These two keys have an array value that contains a key: the host. The rest of the read-write database option is merged from the primary MySQL connection to the array. So, we just need to put the items into the read and write array if we want to overwrite the values in the primary array. So, in this case, 192.168.1.1 will be used as a "read" connection, and while192.168.1.2 will be used as a "write" connection. Database credentials, prefixes, character sets, and all other options in the primary MySQL array will be connected across two shares.

Second, run the query

Once you have configured the database connection, you can run the query class using DB.

Run a Select query

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$results = Db::select (' select * from users where id =? ', array (1));

The selection method of the result always returns an array.

Run an INSERT statement

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Db::insert (' INSERT into users (ID, name) VALUES (?,?) ', Array (1, ' Dayle '));

Run an UPDATE statement

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Db::update (' update users set votes = + WHERE name =? ', Array (' John ') ');

Run a DELETE statement

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DB::d elete (' Delete from users ');

Note: The update and DELETE statements affect the number of rows returned by the action.

Run a general Declaration

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Db::statement (' drop table users ');

Querying for event snooping

You can query the event listener using DB:: Listening method:

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Db::listen (function ($sql, $bindings, $time) {//});

Third, database transactions

To run a set of operations on a database transaction, you can use the transaction method:
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Db::transaction (function () {db::table (' users ')->update (Array (' votes ')
= 1)); Db::table (' posts ')->delete ();});

Note: Any exception thrown in the transaction will cause the automatic transaction to be rolled back

Sometimes you may need to start a transaction:

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Db::begintransaction ();

You can roll back the transaction by rolling back the method:

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Db::rollback ();

Finally, you can submit a transaction by submitting the method:

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Db::commit ();

Iv. Access connections

When using multiple connections, you can access them through the DB:: Connection method:

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$users = db::connection (' foo ')->select (...);

You can also access the original, potential PDO instances:
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$pdo = Db::connection ()->getpdo ();

Sometimes you may need to reconnect to a given database:
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Db::reconnect (' foo ');

If you need to disconnect from the given database will exceed the underlying PDO instance ' smax_connections limit, use the Disconnect method:
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DB::d isconnect (' foo ');

V. Inquiry LOG

By default, the Laravel log saves all queries in memory to run the current request. However, in some cases, such as when the number of rows is inserted, this may cause the application to use extra memory. To disable logging, you can use the Disablequerylog method:

Copy the Code code as follows:
Db::connection ()->disablequerylog ();

O get a set of executed queries, you can use the Getquerylog method:
Copy the Code code as follows:
$queries = Db::getquerylog ();

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