, (*1)
CodeIgniter Model
CodeIgniter 3 Active Record (ORM) Standard Model supported Read & Write Connections, (*2)
, (*3)
This ORM Model extension is collected into yidas/codeigniter-pack which is a complete solution for Codeigniter framework., (*4)
FEATURES
This package provide Base Model which extended CI_Model and provided full CRUD methods to make developing database interactions easier and quicker for your CodeIgniter applications., (*9)
OUTLINE
DEMONSTRATION
ActiveRecord (ORM)
$this->load->model('Posts_model');
// Create an Active Record
$post = new Posts_model;
$post->title = 'CI3'; // Equivalent to `$post['title'] = 'CI3';`
$post->save();
// Update the Active Record found by primary key
$post = $this->Posts_model->findOne(1);
if ($post) {
$oldTitle = $post->title; // Equivalent to `$oldTitle = $post['title'];`
$post->title = 'New CI3';
$post->save();
}
The pattern is similar to Yii2 Active Record and Laravel Eloquent, (*10)
Find with Query Builder
Start to use CodeIgniter Query Builder from find() method, the Model will automatically load its own database connections and data tables., (*11)
$records = $this->Posts_model->find()
->select('*')
->where('is_public', '1')
->limit(25)
->order_by('id')
->get()
->result_array();
CRUD
$result = $this->Posts_model->insert(['title' => 'Codeigniter Model']);
// Find out the record which just be inserted
$record = $this->Posts_model->find()
->order_by('id', 'DESC')
->get()
->row_array();
// Update the record
$result = $this->Posts_model->update(['title' => 'CI3 Model'], $record['id']);
// Delete the record
$result = $this->Posts_model->delete($record['id']);
REQUIREMENTS
This library requires the following:, (*12)
- PHP 5.4.0+
- CodeIgniter 3.0.0+
INSTALLATION
Run Composer in your Codeigniter project under the folder \application:, (*13)
composer require yidas/codeigniter-model
Check Codeigniter application/config/config.php:, (*14)
$config['composer_autoload'] = TRUE;
You could customize the vendor path into $config['composer_autoload'], (*15)
CONFIGURATION
After installation, yidas\Model class is ready to use. Simply, you could create a model to extend the yidas\Model directly:, (*16)
class Post_model extends yidas\Model {}
After that, this model is ready to use for example: $this->PostModel->findOne(123);, (*17)
However, the schema of tables such as primary key in your applicaiton may not same as default, and it's annoying to defind repeated schema for each model. We recommend you to make My_model to extend yidas\Model instead., (*18)
Use My_model to Extend Base Model for every Models
You could use My_model to extend yidas\Model, then make each model to extend My_model in Codeigniter application., (*19)
1. Create My_model extended yidas\Model with configuration for fitting your common table schema:, (*20)
class My_model extends yidas\Model
{
protected $primaryKey = 'sn';
const CREATED_AT = 'created_time';
const UPDATED_AT = 'updated_time';
// Customized Configurations for your app...
}
2. Create each Model extended My_model in application with its own table configuration:, (*21)
class Post_model extends My_model
{
protected $table = "post_table";
}
3. Use each extended Model with library usages:, (*22)
$this->load->model('post_model', 'PostModel');
$post = $this->PostModel->findOne(123);
My_model Example with Document, (*23)
DEFINING MODELS
To get started, let's create an model extends yidas\Model or through My_model, then define each model suitably., (*24)
Table Names
By convention, the "snake case" with lowercase excluded _model postfix of the class name will be used as the table name unless another name is explicitly specified. So, in this case, Model will assume the Post_model model stores records in the post table. You may specify a custom table by defining a table property on your model:, (*25)
// class My_model extends yidas\Model
class Post_model extends My_model
{
protected $table = "post_table";
}
You could set table alias by defining protected $alias = 'A1'; for model., (*26)
Table Name Guessing Rule
In our pattern, The naming between model class and table is the same, with supporting no matter singular or plural names:, (*27)
| Model Class Name |
Table Name |
| Post_model |
post |
| Posts_model |
posts |
| User_info_model |
user_info |
Get Table Name
You could get table name from each Model:, (*28)
$tableName = $this->PostModel->getTable();
Primary Keys
You may define a protected $primaryKey property to override this convention:, (*29)
class My_model extends yidas\Model
{
protected $primaryKey = "sn";
}
Correct primary key setting of Model is neceesary for Active Record (ORM)., (*30)
Timestamps
By default, Model expects created_at and updated_at columns to exist on your tables. If you do not wish to have these columns automatically managed by base Model, set the $timestamps property on your model as false:, (*31)
class My_model extends yidas\Model
{
protected $timestamps = false;
}
If you need to customize the format of your timestamps, set the $dateFormat property on your model. This property determines how date attributes are stored in the database:, (*32)
class My_model extends yidas\Model
{
/**
* Date format for timestamps.
*
* @var string unixtime(946684800)|datetime(2000-01-01 00:00:00)
*/
protected $dateFormat = 'datetime';
}
If you need to customize the names of the columns used to store the timestamps, you may set the CREATED_AT and UPDATED_AT constants in your model:, (*33)
class My_model extends yidas\Model
{
const CREATED_AT = 'created_time';
const UPDATED_AT = 'updated_time';
}
Also, you could customized turn timestamps behavior off for specified column by assigning as empty:, (*34)
class My_model extends yidas\Model
{
const CREATED_AT = 'created_time';
const UPDATED_AT = NULL;
}
Database Connection
By default, all models will use the default database connection $this->db configured for your application. If you would like to specify a different connection for the model, use the $database property:, (*35)
class My_model extends yidas\Model
{
protected $database = 'database2';
}
More Database Connection settings: Read & Write Connections, (*36)
Other settings
class My_model extends yidas\Model
{
// Enable ORM property check for write
protected $propertyCheck = true;
}
BASIC USAGE
Above usage examples are calling Models out of model, for example in controller:, (*37)
$this->load->model('post_model', 'Model');
If you call methods in Model itself, just calling $this as model. For example, $this->find()... for find();, (*38)
Methods
find()
Create an existent CI Query Builder instance with Model features for query purpose., (*39)
public CI_DB_query_builder find(boolean $withAll=false)
Example:, (*40)
$records = $this->Model->find()
->select('*')
->where('is_public', '1')
->limit(25)
->order_by('id')
->get()
->result_array();
// Without any scopes & conditions for this query
$records = $this->Model->find(true)
->where('is_deleted', '1')
->get()
->result_array();
// This is equal to find(true) method
$this->Model->withAll()->find();
After starting find() from a model, it return original CI_DB_query_builder for chaining. The query builder could refer CodeIgniter Query Builder Class Document, (*41)
Query Builder Implementation
You could assign Query Builder as a variable to handle add-on conditions instead of using $this->Model->getBuilder()., (*42)
$queryBuilder = $this->Model->find();
if ($filter) {
$queryBuilder->where('filter', $filter);
}
$records = $queryBuilder->get()->result_array();
reset()
reset an CI Query Builder instance with Model., (*43)
public self reset()
Example:, (*44)
$this->Model->reset()->find();
insert()
Insert a row with Timestamps feature into the associated database table using the attribute values of this record., (*45)
public boolean insert(array $attributes, $runValidation=true)
Example:, (*46)
$result = $this->Model->insert([
'name' => 'Nick Tsai',
'email' => 'myintaer@gmail.com',
]);
batchInsert()
Insert a batch of rows with Timestamps feature into the associated database table using the attribute values of this record., (*47)
public integer batchInsert(array $data, $runValidation=true)
Example:, (*48)
$result = $this->Model->batchInsert([
['name' => 'Nick Tsai', 'email' => 'myintaer@gmail.com'],
['name' => 'Yidas', 'email' => 'service@yidas.com']
]);
replace()
Replace a row with Timestamps feature into the associated database table using the attribute values of this record., (*49)
public boolean replace(array $attributes, $runValidation=true)
Example:, (*50)
$result = $this->Model->replace([
'id' => 1,
'name' => 'Nick Tsai',
'email' => 'myintaer@gmail.com',
]);
update()
Save the changes with Timestamps feature to the selected record(s) into the associated database table., (*51)
public boolean update(array $attributes, array|string $condition=NULL, $runValidation=true)
Example:, (*52)
$result = $this->Model->update(['status'=>'off'], 123)
// Find conditions first then call again
$this->Model->find()->where('id', 123);
$result = $this->Model->update(['status'=>'off']);
// Counter set usage equal to `UPDATE mytable SET count = count+1 WHERE id = 123`
$this->Model->getDB()->set('count','count + 1', FALSE);
$this->Model->find()->where('id', 123);
$result = $this->Model->update([]);
Notice: You need to call update from Model but not from CI-DB builder chain, the wrong sample code:, (*53)
$this->Model->find()->where('id', 123)->update('table', ['status'=>'off']);, (*54)
batchUpdate()
Update a batch of update queries into combined query strings., (*55)
public integer batchUpdate(array $dataSet, boolean $withAll=false, interger $maxLength=4*1024*1024, $runValidation=true)
Example:, (*56)
$result = $this->Model->batchUpdate([
[['title'=>'A1', 'modified'=>'1'], ['id'=>1]],
[['title'=>'A2', 'modified'=>'1'], ['id'=>2]],
]);
delete()
Delete the selected record(s) with Timestamps feature into the associated database table., (*57)
public boolean delete(array|string $condition=NULL, boolean $forceDelete=false, array $attributes=[])
Example:, (*58)
$result = $this->Model->delete(123)
// Find conditions first then call again
$this->Model->find()->where('id', 123);
$result = $this->Model->delete();
// Force delete for SOFT_DELETED mode
$this->Model->delete(123, true);
getLastInsertID()
Get the insert ID number when performing database inserts., (*59)
Example:, (*60)
$result = $this->Model->insert(['name' => 'Nick Tsai']);
$lastInsertID = $this->Model->getLastInsertID();
getAffectedRows()
Get the number of affected rows when doing “write” type queries (insert, update, etc.)., (*61)
public integer|string getLastInsertID()
Example:, (*62)
$result = $this->Model->update(['name' => 'Nick Tsai'], 32);
$affectedRows = $this->Model->getAffectedRows();
count()
Get count from query, (*63)
public integer count(boolean $resetQuery=true)
Example:, (*64)
$result = $this->Model->find()->where("age <", 20);
$totalCount = $this->Model->count();
setAlias()
Set table alias, (*65)
public self setAlias(string $alias)
Example:, (*66)
$query = $this->Model->setAlias("A1")
->find()
->join('table2 AS A2', 'A1.id = A2.id');
ACTIVE RECORD (ORM)
Active Record provides an object-oriented interface for accessing and manipulating data stored in databases. An Active Record Model class is associated with a database table, an Active Record instance corresponds to a row of that table, and an attribute of an Active Record instance represents the value of a particular column in that row., (*67)
Active Record (ORM) supported events such as timestamp for insert and update., (*68)
Inserts
To create a new record in the database, create a new model instance, set attributes on the model, then call the save method:, (*69)
$this->load->model('Posts_model');
$post = new Posts_model;
$post->title = 'CI3';
$result = $post->save();
Updates
The save method may also be used to update models that already exist in the database. To update a model, you should retrieve it, set any attributes you wish to update, and then call the save method:, (*70)
$this->load->model('Posts_model');
$post = $this->Posts_model->findOne(1);
if ($post) {
$post->title = 'New CI3';
$result = $post->save();
}
Deletes
To delete a active record, call the delete method on a model instance:, (*71)
$this->load->model('Posts_model');
$post = $this->Posts_model->findOne(1);
$result = $post->delete();
delete() supports soft deleted and points to self if is Active Record., (*72)
Accessing Data
You could access the column values by accessing the attributes of the Active Record instances likes $activeRecord->attribute, or get by array key likes $activeRecord['attribute']., (*73)
$this->load->model('Posts_model');
// Set attributes
$post = new Posts_model;
$post->title = 'CI3';
$post['subtitle'] = 'PHP';
$post->save();
// Get attributes
$post = $this->Posts_model->findOne(1);
$title = $post->title;
$subtitle = $post['subtitle'];
Relationships
Database tables are often related to one another. For example, a blog post may have many comments, or an order could be related to the user who placed it. This library makes managing and working with these relationships easy, and supports different types of relationships:, (*74)
To work with relational data using Active Record, you first need to declare relations in models. The task is as simple as declaring a relation method for every interested relation, like the following,, (*75)
class CustomersModel extends yidas\Model
{
// ...
public function orders()
{
return $this->hasMany('OrdersModel', ['customer_id' => 'id']);
}
}
Once the relationship is defined, we may retrieve the related record using dynamic properties. Dynamic properties allow you to access relationship methods as if they were properties defined on the model:, (*76)
$orders = $this->CustomersModel->findOne(1)->orders;
The dynamic properties' names are same as methods' names, like Laravel Eloquent, (*77)
For Querying Relations, You may query the orders relationship and add additional constraints with CI Query Builder to the relationship like so:, (*78)
$customer = $this->CustomersModel->findOne(1)
$orders = $customer->orders()->where('active', 1)->get()->result_array();
Methods
findOne()
Return a single active record model instance by a primary key or an array of column values., (*79)
public object findOne(array $condition=[])
Example:, (*80)
// Find a single active record whose primary key value is 10
$activeRecord = $this->Model->findOne(10);
// Find the first active record whose type is 'A' and whose status is 1
$activeRecord = $this->Model->findOne(['type' => 'A', 'status' => 1]);
// Query builder ORM usage
$this->Model->find()->where('id', 10);
$activeRecord = $this->Model->findOne();
findAll()
Returns a list of active record models that match the specified primary key value(s) or a set of column values., (*81)
public array findAll(array $condition=[], integer|array $limit=null)
Example:, (*82)
// Find the active records whose primary key value is 10, 11 or 12.
$activeRecords = $this->Model->findAll([10, 11, 12]);
// Find the active recordd whose type is 'A' and whose status is 1
$activeRecords = $this->Model->findAll(['type' => 'A', 'status' => 1]);
// Query builder ORM usage
$this->Model->find()->where_in('id', [10, 11, 12]);
$activeRecords = $this->Model->findAll();
// Print all properties for each active record from array
foreach ($activeRecords as $activeRecord) {
print_r($activeRecord->toArray());
}
Example of limit:, (*83)
// LIMIT 10
$activeRecords = $this->Model->findAll([], 10);
// OFFSET 50, LIMIT 10
$activeRecords = $this->Model->findAll([], [50, 10]);
save()
Active Record (ORM) save for insert or update, (*84)
public boolean save(boolean $runValidation=true)
beforeSave()
This method is called at the beginning of inserting or updating a active record, (*85)
public boolean beforeSave(boolean $insert)
Example:, (*86)
public function beforeSave($insert)
{
if (!parent::beforeSave($insert)) {
return false;
}
// ...custom code here...
return true;
}
afterSave()
This method is called at the end of inserting or updating a active record, (*87)
public boolean beforeSave(boolean $insert, array $changedAttributes)
hasOne()
Declares a has-one relation, (*88)
public CI_DB_query_builder hasOne(string $modelName, string $foreignKey=null, string $localKey=null)
Example:, (*89)
class OrdersModel extends yidas\Model
{
// ...
public function customer()
{
return $this->hasOne('CustomersModel', 'id', 'customer_id');
}
}
Accessing Relational Data:, (*90)
$this->load->model('OrdersModel');
// SELECT * FROM `orders` WHERE `id` = 321
$order = $this->OrdersModel->findOne(321);
// SELECT * FROM `customers` WHERE `customer_id` = 321
// $customer is a Customers active record
$customer = $order->customer;
hasMany()
Declares a has-many relation, (*91)
public CI_DB_query_builder hasMany(string $modelName, string $foreignKey=null, string $localKey=null)
Example:, (*92)
class CustomersModel extends yidas\Model
{
// ...
public function orders()
{
return $this->hasMany('OrdersModel', 'customer_id', 'id');
}
}
Accessing Relational Data:, (*93)
$this->load->model('CustomersModel');
// SELECT * FROM `customers` WHERE `id` = 123
$customer = $this->CustomersModel->findOne(123);
// SELECT * FROM `order` WHERE `customer_id` = 123
// $orders is an array of Orders active records
$orders = $customer->orders;
toArray()
Active Record transform to array record, (*94)
public array toArray()
Example:, (*95)
if ($activeRecord)
$record = $activeRecord->toArray();
It's recommended to use find() with CI builder instead of using ORM and turning it to array., (*96)
SOFT DELETED
In addition to actually removing records from your database, This Model can also "soft delete" models. When models are soft deleted, they are not actually removed from your database. Instead, a deleted_at attribute could be set on the model and inserted into the database., (*97)
Configuration
You could enable SOFT DELETED feature by giving field name to SOFT_DELETED:, (*98)
class My_model extends yidas\Model
{
const SOFT_DELETED = 'is_deleted';
}
While SOFT_DELETED is enabled, you could set $softDeletedFalseValue and $softDeletedTrueValue for fitting table schema. Futher, you may set DELETED_AT with column name for Timestapes feature, or disabled by setting to NULL by default:, (*99)
class My_model extends yidas\Model
{
const SOFT_DELETED = 'is_deleted';
// The actived value for SOFT_DELETED
protected $softDeletedFalseValue = '0';
// The deleted value for SOFT_DELETED
protected $softDeletedTrueValue = '1';
const DELETED_AT = 'deleted_at';
}
If you need to disabled SOFT DELETED feature for specified model, you may set SOFT_DELETED to false, which would disable any SOFT DELETED functions including DELETED_AT feature:, (*100)
// class My_model extends yidas\Model
class Log_model extends My_model
{
const SOFT_DELETED = false;
}
Methods
forceDelete()
Force Delete the selected record(s) with Timestamps feature into the associated database table., (*101)
public boolean forceDelete($condition=null)
Example:, (*102)
$result = $this->Model->forceDelete(123)
// Query builder ORM usage
$this->Model->find()->where('id', 123);
$result = $this->Model->forceDelete();
restore()
Restore SOFT_DELETED field value to the selected record(s) into the associated database table., (*103)
public boolean restore($condition=null)
Example:, (*104)
$result = $this->Model->restore(123)
// Query builder ORM usage
$this->Model->withTrashed()->find()->where('id', 123);
$this->Model->restore();
withTrashed()
Without SOFT DELETED query conditions for next find(), (*105)
public self withTrashed()
Example:, (*106)
$this->Model->withTrashed()->find();
QUERY SCOPES
Query scopes allow you to add constraints to all queries for a given model. Writing your own global scopes can provide a convenient, easy way to make sure every query for a given model receives certain constraints. The SOFT DELETED scope is a own scope which is not includes in global scope., (*107)
Configuration
You could override _globalScopes method to define your constraints:, (*108)
class My_model extends yidas\Model
{
protected $userAttribute = 'uid';
/**
* Override _globalScopes with User validation
*/
protected function _globalScopes()
{
$this->db->where(
$this->_field($this->userAttribute),
$this->config->item('user_id')
);
return parent::_globalScopes();
}
After overriding that, the My_model will constrain that scope in every query from find(), unless you remove the query scope before a find query likes withoutGlobalScopes()., (*109)
Methods
withoutGlobalScopes()
Without Global Scopes query conditions for next find(), (*110)
public self withoutGlobalScopes()
Example:, (*111)
$this->Model->withoutGlobalScopes()->find();
withAll()
Without all query conditions (SOFT DELETED & QUERY SCOPES) for next find(), (*112)
That is, with all data set of Models for next find(), (*113)
public self withAll()
Example:, (*114)
$this->Model->withAll()->find();
VALIDATION
As a rule of thumb, you should never trust the data received from end users and should always validate it before putting it to good use., (*115)
The ORM Model validation integrates CodeIgniter Form Validation that provides consistent and smooth way to deal with model data validation., (*116)
Given a model populated with user inputs, you can validate the inputs by calling the validate() method. The method will return a boolean value indicating whether the validation succeeded or not. If not, you may get the error messages from getErrors() method., (*117)
validate()
Performs the data validation with filters, (*118)
ORM only performs validation for assigned properties., (*119)
public boolean validate($data=[], $returnData=false)
Exmaple:, (*120)
$this->load->model('PostsModel');
if ($this->PostsModel->validate($inputData)) {
// all inputs are valid
} else {
// validation failed: $errors is an array containing error messages
$errors = $this->PostsModel->getErrors();
}
The methods of yidas\Model for modifying such as insert() and update() will also perform validation. You can turn off $runValidation parameter of methods if you ensure that the input data has been validated., (*121)
Exmaple of ORM Model:, (*122)
$this->load->model('PostsModel');
$post = new PostsModel;
$post->title = '';
// ORM assigned or modified attributes will be validated by calling `validate()` without parameters
if ($post->validate()) {
// Already performing `validate()` so that turn false for $runValidation
$result = $post->save(false);
} else {
// validation failed: $errors is an array containing error messages
$errors = post->getErrors();
}
A ORM model's properties will be changed by filter after performing validation. If you have previously called validate().
You can turn off $runValidation of save() for saving without repeated validation., (*123)
getErrors()
Validation - Get error data referenced by last failed Validation, (*124)
public array getErrors()
Declaring Rules
To make validate() really work, you should declare validation rules for the attributes you plan to validate. This should be done by overriding the rules() method with returning CodeIgniter Rules., (*125)
rules()
Returns the validation rules for attributes., (*126)
public array rules()
Example:, (*127)
class PostsModel extends yidas\Model
{
protected $table = "posts";
/**
* Override rules function with validation rules setting
*/
public function rules()
{
return [
[
'field' => 'title',
'rules' => 'required|min_length[3]',
],
];
}
}
The returning array format could refer CodeIgniter - Setting Rules Using an Array, and the rules pattern could refer CodeIgniter - Rule Reference, (*128)
Error Message with Language
When you are dealing with i18n issue of validation's error message, you can integrate CodeIgniter language class into rules. The following sample code is available for you to implement:, (*129)
public function rules()
{
/**
* Set CodeIgniter language
* @see https://www.codeigniter.com/userguide3/libraries/language.html
*/
$this->lang->load('error_messages', 'en-US');
return [
[
'field' => 'title',
'rules' => 'required|min_length[3]',
'errors' => [
'required' => $this->lang->line('required'),
'min_length' => $this->lang->line('min_length'),
],
],
];
}
In above case, the language file could be application/language/en-US/error_messages_lang.php:, (*130)
$lang['required'] = '`%s` is required';
$lang['min_length'] = '`%s` requires at least %d letters';
After that, the getErrors() could returns field error messages with current language., (*131)
Filters
User inputs often need to be filtered or preprocessed. For example, you may want to trim the spaces around the username input. You may declare filter rules in filter() method to achieve this goal., (*132)
In model's validate() process, the filters() will be performed before rules(), which means the input data validated by rules() is already be filtered., (*133)
To enable filters for validate(), you should declare filters for the attributes you plan to perform. This should be done by overriding the filters() method., (*134)
filters()
Returns the filter rules for validation., (*135)
public array filters()
Example:, (*136)
public function filters()
{
return [
[['title', 'name'], 'trim'], // Perform `trim()` for title & name input data
[['title'], 'static::method'], // Perform `public static function method($value)` in this model
[['name'], function($value) { // Perform defined anonymous function. 'value' => '[Filtered]value'
return "[Filtered]" . $value;
}],
[['content'], [$this->security, 'xss_clean']], // Perform CodeIgniter XSS Filtering for content input data
];
}
The filters format: [[['attr1','attr2'], callable],], (*137)
READ & WRITE CONNECTIONS
Sometimes you may wish to use one database connection for SELECT statements, and another for INSERT, UPDATE, and DELETE statements. This Model implements Replication and Read-Write Splitting, makes database connections will always be used while using Model usages., (*138)
Configuration
Read & Write Connections could be set in the model which extends yidas\Model, you could defind the read & write databases in extended My_model for every models., (*139)
There are three types to set read & write databases:, (*140)
Codeigniter DB Connection
It recommends to previously prepare CI DB connections, you could assign to attributes directly in construct section before parent's constrcut:, (*141)
class My_model extends yidas\Model
{
function __construct()
{
$this->database = $this->db;
$this->databaseRead = $this->dbr;
parent::__construct();
}
}
If you already have $this->db, it would be the default setting for both connection., (*142)
This setting way supports Reconnection., (*143)
Codeigniter Database Key
You could set the database key refered from \application\config\database.php into model attributes of database & databaseRead, the setting connections would be created automatically:, (*144)
class My_model extends yidas\Model
{
protected $database = 'default';
protected $databaseRead = 'slave';
}
This method supports cache mechanism for DB connections, each model could define its own connections but share the same connection by key., (*145)
Codeigniter Database Config Array
This way is used for the specified model related to the one time connected database in a request cycle, which would create a new connection per each model:, (*146)
class My_model extends yidas\Model
{
protected $databaseRead = [
'dsn' => '',
'hostname' => 'specified_db_host',
// Database Configuration...
];
}
Load Balancing for Databases
In above case, you could set multiple databases and implement random selected connection for Read or Write Databases., (*147)
For example, configuring read databases in application/config/database:, (*148)
$slaveHosts = ['192.168.1.2', '192.168.1.3'];
$db['slave']['hostname'] = $slaveHosts[mt_rand(0, count($slaveHosts) - 1)];
After that, you could use database key slave to load or assign it to attribute:, (*149)
class My_model extends yidas\Model
{
protected $databaseRead = 'slave';
}
Reconnection
If you want to reconnect database for reestablishing the connection in Codeigniter 3, for $this->db example:, (*150)
$this->db->close();
$this->db->initialize();
The model connections with Codeigniter DB Connection setting could be reset after reset the referring database connection., (*151)
Do NOT use reconnect() which is a useless method., (*152)
PESSIMISTIC LOCKING
The Model also includes a few functions to help you do "pessimistic locking" on your select statements. To run the statement with a "shared lock", you may use the sharedLock method to get a query. A shared lock prevents the selected rows from being modified until your transaction commits:, (*153)
$this->Model->find()->where('id', 123);
$result = $this->Model->sharedLock()->row_array();
Alternatively, you may use the lockForUpdate method. A "for update" lock prevents the rows from being modified or from being selected with another shared lock:, (*154)
$this->Model->find()->where('id', 123);
$result = $this->Model->lockForUpdate()->row_array();
Example Code
This transaction block will lock selected rows for next same selected rows with FOR UPDATE lock:, (*155)
$this->Model->getDB()->trans_start();
$this->Model->find()->where('id', 123)
$result = $this->Model->lockForUpdate()->row_array();
$this->Model->getDB()->trans_complete();
HELPERS
The model provides several helper methods:, (*156)
indexBy()
Index by Key, (*157)
public array indexBy(array & $array, Integer $key=null, Boolean $obj2Array=false)
Example:, (*158)
$records = $this->Model->findAll();
$this->Model->indexBy($records, 'sn');
// Result example of $records:
[
7 => ['sn'=>7, title=>'Foo'],
13 => ['sn'=>13, title=>'Bar']
]
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