The db class of ThinkPHP5 is a database operation class that encapsulates PDO. It is very convenient to use. This article will introduce how to use the db class.

1. Connect to the database

There are two ways to connect to the database, one is to configure it in config.php, and the other is to pass in the connection parameters when instantiating the Db class.

Configure in config.php:

return?[
????//?數(shù)據(jù)庫類型
????'type'??????=>?'mysql',
????//?服務(wù)器地址
????'hostname'??=>?'127.0.0.1',
????//?數(shù)據(jù)庫名
????'database'??=>?'test',
????//?數(shù)據(jù)庫用戶名
????'username'??=>?'root',
????//?數(shù)據(jù)庫密碼
????'password'??=>?'',
????//?數(shù)據(jù)庫連接端口
????'hostport'??=>?'',
];

Pass in the connection parameters when instantiating the Db class:

use?think\Db;

$config?=?[
????//?數(shù)據(jù)庫類型
????'type'??????=>?'mysql',
????//?服務(wù)器地址
????'hostname'??=>?'127.0.0.1',
????//?數(shù)據(jù)庫名
????'database'??=>?'test',
????//?數(shù)據(jù)庫用戶名
????'username'??=>?'root',
????//?數(shù)據(jù)庫密碼
????'password'??=>?'',
????//?數(shù)據(jù)庫連接端口
????'hostport'??=>?'',
];

Db::connect($config);

2. Basic operations

1. Query Operation

use?think\Db;

//查詢一條數(shù)據(jù)
Db::table('user')->where('id',?1)->find();

//查詢多條數(shù)據(jù)
Db::table('user')->where('age',?'>',?18)->select();

2. Insert operation

use?think\Db;

$data?=?[
????'username'?=>?'admin',
????'password'?=>?md5('admin'),
????'sex'??????=>?1,
????'age'??????=>?20,
];

Db::table('user')->insert($data);

3. Update operation

use?think\Db;

Db::table('user')->where('id',?1)->update(['age'?=>?21]);

4. Delete operation

use?think\Db;

Db::table('user')->where('id',?1)->delete();

3. Advanced operation

1.Chain operation

Chain operation can simplify the writing of sql statements.

use?think\Db;

Db::table('user')
????->alias('u')
????->join('role?r',?'u.role_id=r.id')
????->where('u.id',?1)
????->field('u.username,?r.name')
????->find();

2. Debugging methods

In the development environment, we often need to check the execution of sql statements. The Db class provides three debugging methods: getLastSql, getExplain and getSqlLog.

use?think\Db;

Db::table('user')->getLastSql();

Db::table('user')->where('age',?'>',?18)->getExplain();

Db::table('user')->where('age',?'>',?18)->select();
Db::table('user')->getLastSql();

print_r(Db::getSqlLog());

The getLastSql method can obtain the last executed sql statement.

The getExplain method can obtain the execution plan of the sql statement.

The getSqlLog method can obtain all executed sql statements and execution time.

4. Summary

The above is how to use the db class of ThinkPHP5. The db class provides a very convenient way to operate the database, and you can choose to use it according to your needs during development. If you encounter problems when using the db class, you can refer to the official documentation or ask questions in the relevant forums.

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