PHP实例开发源码—CakePHP编写的开源Web应用框架.zip

[](https://packagist.org/packages/cakephp/database) [](LICENSE.txt) # A flexible and lightweight Database Library for PHP This library abstracts and provides help with most aspects of dealing with relational databases such as keeping connections to the server, building queries, preventing SQL injections, inspecting and altering schemas, and with debugging and profiling queries sent to the database. It adopts the API from the native PDO extension in PHP for familiarity, but solves many of the inconsistencies PDO has, while also providing several features that extend PDO's capabilities. A distinguishing factor of this library when compared to similar database connection packages, is that it takes the concept of "data types" to its core. It lets you work with complex PHP objects or structures that can be passed as query conditions or to be inserted in the database. The typing system will intelligently convert the PHP structures when passing them to the database, and convert them back when retrieving. ## Connecting to the database This library is able to work with the following databases: * MySQL * Postgres * SQLite * Microsoft SQL Server (2008 and above) The first thing you need to do when using this library is create a connection object. Before performing any operations with the connection, you need to specify a driver to use: ```php use Cake\Database\Connection; use Cake\Database\Driver\Mysql; $driver = new Mysql([ 'database' => 'test', 'username' => 'root', 'password' => 'secret' ]); $connection = new Connection([ 'driver' => $driver ]); ``` Drivers are classes responsible for actually executing the commands to the database and correctly building the SQL according to the database specific dialect. Drivers can also be specified by passing a class name. In that case, include all the connection details directly in the options array: ```php use Cake\Database\Connection; $connection = new Connection([ 'driver' => 'Cake\Database\Driver\Sqlite', 'database' => '/path/to/file.db' ]); ``` ### Connection options This is a list of possible options that can be passed when creating a connection: * `persistent`: Creates a persistent connection * `host`: The server host * `database`: The database name * `username`: Login credential * `password`: Connection secret * `encoding`: The connection encoding (or charset) * `timezone`: The connection timezone or time offset ## Using connections After creating a connection, you can immediately interact with the database. You can choose either to use the shorthand methods `execute()`, `insert()`, `update()`, `delete()` or use the `newQuery()` for using a query builder. The easiest way of executing queries is by using the `execute()` method, it will return a `Cake\Database\StatementInterface` that you can use to get the data back: ```php $statement = $connection->execute('SELECT * FROM articles'); while($row = $statement->fetch('assoc')) { echo $row['title'] . PHP_EOL; } ``` Binding values to parametrized arguments is also possible with the execute function: ```php $statement = $connection->execute('SELECT * FROM articles WHERE id = :id', ['id' => 1], ['id' => 'integer']); $results = $statement->fetch('assoc'); ``` The third parameter is the types the passed values should be converted to when passed to the database. If no types are passed, all arguments will be interpreted as a string. Alternatively you can construct a statement manually and then fetch rows from it: ```php $statement = $connection->prepare('SELECT * from articles WHERE id != :id'); $statement->bind(['id' => 1], ['id' => 'integer']); $results = $statement->fetchAll('assoc'); ``` The default types that are understood by this library and can be passed to the `bind()` function or to `execute()` are: * biginteger * binary * date * float * decimal * integer * time * datetime * timestamp * uuid More types can be added dynamically in a bit. Statements can be reused by binding new values to the parameters in the query: ```php $statement = $connection->prepare('SELECT * from articles WHERE id = :id'); $statement->bind(['id' => 1], ['id' => 'integer']); $results = $statement->fetchAll('assoc'); $statement->bind(['id' => 1], ['id' => 'integer']); $results = $statement->fetchAll('assoc'); ``` ### Updating Rows Updating can be done using the `update()` function in the connection object. In the following example we will update the title of the article with id = 1: ```php $connection->update('articles', ['title' => 'New title'], ['id' => 1]); ``` The concept of data types is central to this library, so you can use the last parameter of the function to specify what types should be used: ```php $connection->update( 'articles', ['title' => 'New title'], ['created >=' => new DateTime('-3 day'), 'created <' => new DateTime('now')], ['created' => 'datetime'] ); ``` The example above will execute the following SQL: ```sql UPDATE articles SET title = 'New Title' WHERE created >= '2014-10-10 00:00:00' AND created < '2014-10-13 00:00:00'; ``` More on creating complex where conditions or more complex update queries later. ### Deleting Rows Similarly, the `delete()` method is used to delete rows from the database: ```php $connection->delete('articles', ['created <' => DateTime('now')], ['created' => 'date']); ``` Will generate the following SQL ```sql DELETE FROM articles where created < '2014-10-10' ``` ### Inserting Rows Rows can be inserted using the `insert()` method: ```php $connection->insert( 'articles', ['title' => 'My Title', 'body' => 'Some paragraph', 'created' => new DateTime()], ['created' => 'datetime'] ); ``` More complex updates, deletes and insert queries can be generated using the `Query` class. ## Query Builder One of the goals of this library is to allow the generation of both simple and complex queries with ease. The query builder can be accessed by getting a new instance of a query: ```php $query = $connection->newQuery(); ``` ### Selecting Fields Adding fields to the `SELECT` clause: ```php $query->select(['id', 'title', 'body']); // Results in SELECT id AS pk, title AS aliased_title, body ... $query->select(['pk' => 'id', 'aliased_title' => 'title', 'body']); // Use a closure $query->select(function ($query) { return ['id', 'title', 'body']; }); ``` ### Where Conditions Generating conditions: ```php // WHERE id = 1 $query->where(['id' => 1]); // WHERE id > 2 $query->where(['id >' => 1]); ``` As you can see you can use any operator by placing it with a space after the field name. Adding multiple conditions is easy as well: ```php $query->where(['id >' => 1])->andWhere(['title' => 'My Title']); // Equivalent to $query->where(['id >' => 1, 'title' => 'My title']); ``` It is possible to generate `OR` conditions as well ```php $query->where(['OR' => ['id >' => 1, 'title' => 'My title']]); ``` For even more complex conditions you can use closures and expression objects: ```php $query->where(function ($exp) { return $exp ->eq('author_id', 2) ->eq('published', true) ->notEq('spam', true) ->gt('view_count', 10); }); ``` Which results in: ```sql SELECT * FROM articles WHERE author_id = 2 AND published = 1 AND spam != 1 AND view_count > 10 ``` Combining expressions is also possible: ```php $query->where(function ($exp) { $orConditions = $exp->or(['author_id' => 2]) ->eq('author_id', 5); return $exp ->not($orConditions) ->lte('view_count', 10); }); ``` That generates: ```sql SELECT * FROM articles WHERE NOT (author_id = 2 OR author_id = 5) AND view_count <= 10 ``` When using the expression objects you can use the following methods to create conditions: * `eq()` Creates an equality condition. * `n