在我们的项目中有时可能需要连接不止一个数据库，在ci中如何实现呢？
我们在本地新建了两个数据库，，如下截图所示：
修改配置文件database.php文件为如下格式（读者根据自己数据库的情况修改相应参数的配置）：
<?phpdefined('BASEPATH') OR exit('No direct script access allowed');/*| ——————————————————————-| DATABASE CONNECTIVITY SETTINGS| ——————————————————————-| This file will contain the settings needed to access your database.|| For complete instructions please consult the 'Database Connection'| page of the User Guide.|| ——————————————————————-| EXPLANATION OF VARIABLES| ——————————————————————-||['dsn']The full DSN string describe a connection to the database.|['hostname'] The hostname of your database server.|['username'] The username used to connect to the database|['password'] The password used to connect to the database|['database'] The name of the database you want to connect to|['dbdriver'] The database driver. e.g.: mysqli.|Currently supported:|cubrid, ibase, mssql, mysql, mysqli, oci8,|odbc, pdo, postgre, sqlite, sqlite3, sqlsrv|['dbprefix'] You can add an optional prefix, which will be added|to the table name when using the Query Builder class|['pconnect'] TRUE/FALSE – Whether to use a persistent connection|['db_debug'] TRUE/FALSE – Whether database errors should be displayed.|['cache_on'] TRUE/FALSE – Enables/disables query caching|['cachedir'] The path to the folder where cache files should be stored|['char_set'] The character set used in communicating with the database|['dbcollat'] The character collation used in communicating with the database|NOTE: For MySQL and MySQLi databases, this setting is only used|as a backup if your server is running PHP < 5.2.3 or MySQL < 5.0.7|(and in table creation queries made with DB Forge).|There is an incompatibility in PHP with mysql_real_escape_string() which|can make your site vulnerable to SQL injection if you are using a|multi-byte character set and are running versions lower than these.|Sites using Latin-1 or UTF-8 database character set and collation are unaffected.|['swap_pre'] A default table prefix that should be swapped with the dbprefix|['encrypt'] Whether or not to use an encrypted connection.|['compress'] Whether or not to use client compression (MySQL only)|['stricton'] TRUE/FALSE – forces 'Strict Mode' connections|- good for ensuring strict SQL while developing|['failover'] array – A array with 0 or more data for connections if the main should fail.|['save_queries'] TRUE/FALSE – Whether to "save" all executed queries.|NOTE: Disabling this will also effectively disable both|$this->db->last_query() and profiling of DB queries.|When you run a query, with this setting set to TRUE (default),|CodeIgniter will store the SQL statement for debugging purposes.|However, this may cause high memory usage, especially if you run|a lot of SQL queries … disable this to avoid that problem.|| The $active_group variable lets you choose which connection group to| make active. By default there is only one group (the 'default' group).|| The $query_builder variables lets you determine whether or not to load| the query builder class.*/$active_group = 'test';//默认连接test数据库$active_record = TRUE;//是否开启active record$db['test'] = array('dsn'=> '','hostname' => 'localhost','username' => 'root','password' => '','database' => 'test','dbdriver' => 'mysqli','dbprefix' => '','pconnect' => FALSE,'db_debug' => TRUE,'cache_on' => FALSE,'cachedir' => '','char_set' => 'utf8','dbcollat' => 'utf8_general_ci','swap_pre' => '','encrypt' => FALSE,'compress' => FALSE,'stricton' => FALSE,'failover' => array(),'save_queries' => TRUE);//test2数据库相关配置$db['test2'] = array('dsn'=> '','hostname' => 'localhost','username' => 'root','password' => '','database' => 'test2','dbdriver' => 'mysqli','dbprefix' => '','pconnect' => FALSE,'db_debug' => TRUE,'cache_on' => FALSE,'cachedir' => '','char_set' => 'utf8','dbcollat' => 'utf8_general_ci','swap_pre' => '','encrypt' => FALSE,'compress' => FALSE,'stricton' => FALSE,'failover' => array(),'save_queries' => TRUE);生活若剥去理想、梦想、幻想，那生命便只是一堆空架子
