# data
**Repository Path**: mirrors_yiisoft/data
## Basic Information
- **Project Name**: data
- **Description**: Data providers
- **Primary Language**: Unknown
- **License**: BSD-3-Clause
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No
## Statistics
- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-08-19
- **Last Updated**: 2026-02-07
## Categories & Tags
**Categories**: Uncategorized
**Tags**: None
## README
Yii Data
[](https://packagist.org/packages/yiisoft/data)
[](https://packagist.org/packages/yiisoft/data)
[](https://github.com/yiisoft/data/actions/workflows/build.yml)
[](https://codecov.io/gh/yiisoft/data)
[](https://dashboard.stryker-mutator.io/reports/github.com/yiisoft/data/master)
[](https://github.com/yiisoft/data/actions?query=workflow%3A%22static+analysis%22)
[](https://shepherd.dev/github/yiisoft/data)
[](https://shepherd.dev/github/yiisoft/data)
The package provides generic data abstractions. The aim is to hide a storage aspect from the operations of reading,
writing and processing data.
Features are:
- Data reader abstraction with counting, sorting, limiting and offsetting, reading criteria filter and post-filter.
- Pagination abstraction along with offset and keyset implementations.
- Data writer abstraction.
- Data processor abstraction.
## Requirements
- PHP 8.1 - 8.5.
## Installation
The package could be installed with [Composer](https://getcomposer.org):
```shell
composer require yiisoft/data
```
## General usage
## Concepts
- Each data set consists of items.
- Each item has multiple named fields.
- All items in a data set have the same structure.
## Reading data
Data reader aim is to read data from a storage such as database, array or API and convert it to a simple iterator of
field => value items.
```php
$reader = new MyDataReader(...);
$result = $reader->read();
```
Result is `iterable` so you can use `foreach` on it. If you need an array, it could be achieved the following way:
```php
// using is foreach
foreach ($result as $item) {
// ...
}
// preparing array
$dataArray = $result instanceof \Traversable ? iterator_to_array($result, true) : (array)$result;
```
### Limiting the number of items to read
You can limit the number of items in an iterator:
```php
$reader = (new MyDataReader(...))->withLimit(10);
foreach ($reader->read() as $item) {
// ...
}
```
### Counting the total number of items
To know total number of items in a data reader implementing `CountableDataInterface`:
```php
$reader = new MyDataReader(...);
$total = count($reader);
```
### Filtering
Filtering of data could be done in two steps:
1. Forming a criteria for getting the data. That is done by "filter."
2. Post-filtering data by iteration and checking each item.
That is done by `IterableDataReader` with filters.
Whenever possible, it is best to stick to using criteria because usually it gives much better performance.
To filter data in a data reader implementing `FilterableDataInterface` you need to supply filter to
`withFilter()` method:
```php
$filter = new AndX(
new GreaterThan('id', 3),
new Like('name', 'agent')
);
$reader = (new MyDataReader(...))
->withFilter($filter);
$data = $reader->read();
```
Filter could be composed with:
- `AndX`
- `Between`
- `Equals`
- `EqualsNull`
- `GreaterThan`
- `GreaterThanOrEqual`
- `ILike`
- `In`
- `LessThan`
- `LessThanOrEqual`
- `Like`
- `Not`
- `OrX`
#### Filtering with arrays
The `AndX` and `OrX` filters have a `withCriteriaArray()` method, which allows you to define filters with arrays.
```php
$dataReader->withFilter((new AndX())->withCriteriaArray([
['=', 'id', 88],
[
'or',
[
['=', 'color', 'red'],
['=', 'state', 1],
]
]
]));
```
#### Implementing your own filter
To have your own filter:
- Implement at least `FilterInterface`, which includes:
- `getOperator()` method that returns a string that represents a filter operation.
- `toArray()` method that returns an array with filtering parameters.
- If you want to create a filter handler for a specific data reader type, then you need to implement at least
`FilterHandlerInterface`. It has a single `getOperator()` method that returns a string representing a filter operation.
Also, each data reader specifies an extended interface required for handling or building the operation.
*For example, `IterableDataFilter` defines `IterableFilterHandlerInterface`, which contains additional `match()`
method to execute a filter on PHP variables.*
You can add your own filter handlers to the data reader using the `withFilterHandlers()` method. You can add any filter
handler to the reader. If a reader is not able to use a filter, filter is ignored.
```php
// own filter for filtering
class OwnNotTwoFilter implements FilterInterface
{
private $field;
public function __construct($field)
{
$this->field = $field;
}
public static function getOperator(): string
{
return 'my!2';
}
public function toArray(): array
{
return [static::getOperator(), $this->field];
}
}
// own iterable filter handler for matching
class OwnIterableNotTwoFilterHandler implements IterableFilterHandlerInterface
{
public function getOperator(): string
{
return OwnNotTwoFilter::getOperator();
}
public function match(array $item, array $arguments, Context $context): bool
{
[$field] = $arguments;
return $item[$field] != 2;
}
}
// and using it on a data reader
$filter = new AndX(
new LessThan('id', 8),
new OwnNotTwoFilter('id'),
);
$reader = (new MyDataReader(...))
->withFilter($filter)
->withFilterHandlers(
new OwnIterableNotTwoFilter()
new OwnSqlNotTwoFilter() // for SQL
// and for any supported readers...
);
$data = $reader->read();
```
### Sorting
To sort data in a data reader implementing `SortableDataInterface` you need to supply a sort object to
`withSort()` method:
```php
$sorting = Sort::only([
'id',
'name'
]);
$sorting = $sorting->withOrder(['name' => 'asc']);
// or $sorting = $sorting->withOrderString('name');
$reader = (new MyDataReader(...))
->withSort($sorting);
$data = $reader->read();
```
The goal of the `Sort` is to map logical fields sorting to real data set fields sorting and form a criteria for the data
reader. Logical fields are the ones user operates with. Real fields are the ones actually present in a data set.
Such a mapping helps when you need to sort by a single logical field that, in fact, consists of multiple fields
in the underlying data set. For example, you provide a user with a username which consists of first name and last name
fields in the actual data set.
To get a `Sort` instance, you can use either `Sort::only()` or `Sort::any()`. `Sort::only()` ignores user-specified order
for logical fields that have no configuration. `Sort::any()` uses user-specified logical field name and order directly
for fields that have no configuration.
Either way, you pass a config array that specifies which logical fields should be order-able and, optionally, details on
how these should map to real fields order.
The current order to apply is specified via `withOrder()` where you supply an array with keys corresponding to logical
field names and values correspond to order (`asc` or `desc`). Alternatively `withOrderString()` can be used. In this case,
ordering is represented as a single string containing comma separate logical field names. If the name is prefixed by `-`,
ordering direction is set to `desc`.
### Skipping some items
In case you need to skip some items from the beginning of data reader implementing `OffsetableDataInterface`:
```php
$reader = (new MyDataReader(...))->withOffset(10);
```
### Implementing your own data reader
To have your own data reader, you need to implement at least `DataReaderInteface`. It has a single `read()`
method that returns iterable representing a set of items.
Additional interfaces could be implemented to support different pagination types, ordering and filtering:
- `CountableDataInterface` - allows getting total number of items in data reader.
- `FilterableDataInterface` - allows returning subset of items based on criteria.
- `LimitableDataInterface` - allows returning limited subset of items.
- `SortableDataInterface` - allows sorting by one or multiple fields.
- `OffsetableDataInterface` - allows skipping first N items when reading data.
Note that when implementing these, methods, instead of modifying data, should only define criteria that is later used
in `read()` to affect what data is returned.
## Pagination
Pagination allows getting a limited subset of data that is both handy for displaying items page by page and for getting
acceptable performance on big data sets.
There are two types of pagination provided: traditional offset pagination and keyset pagination.
### Offset pagination
Offset pagination is a common pagination method that selects OFFSET + LIMIT items and then skips OFFSET items.
Advantages:
- The total number of pages is available
- Can get to specific page
- Data can be unordered
- The limit set in the data reader is taken into account
Disadvantages:
- Performance degrades with page number increase
- Insertions or deletions in the middle of the data are making results inconsistent
Usage is the following:
```php
$reader = (new MyDataReader(...));
$paginator = (new OffsetPaginator($dataReader))
->withPageSize(10)
->withCurrentPage(2);
$total = $paginator->getTotalPages();
$data = $paginator->read();
```
### Keyset pagination
Keyset pagination is an alternative pagination method that is good for infinite scrolling and "load more." It is selecting
LIMIT items that have key field greater or lesser (depending on the sorting) than the value specified.
Advantages:
- Performance doesn't depend on page number
- Consistent results regardless of insertions and deletions
Disadvantages:
- The total number of pages is not available
- Can't get to specific page, only "previous" and "next"
- Data cannot be unordered
- The limit set in the data reader leads to an exception
Usage is the following:
```php
$sort = Sort::only(['id', 'name']);
$dataReader = (new MyDataReader(...))->withSort($sort);
$paginator = (new KeysetPaginator($dataReader))
->withPageSize(10)
->withToken(PageToken::next('13'));
```
When displaying first page ID (or another field name to paginate by) of the item displayed last is used with `withNextPageToken()`
to get next page.
#### Iterate through all pages
Both `OffsetPaginator` and `KeysetPaginator` provide `nextPage()` and `previousPage()` methods for easy page-by-page data reading:
```php
$dataReader = (new QueryDataReader($query))->withSort(Sort::only(['id']));
for (
$paginator = (new KeysetPaginator($dataReader))->withPageSize(1000);
$paginator !== null;
$paginator = $paginator->nextPage()
) {
foreach ($paginator->read() as $data) {
// Process each item
}
}
```
The `nextPage()` method returns a new paginator instance configured for the next page, or `null` when there are no more pages.
Similarly, `previousPage()` returns a paginator for the previous page, or `null` when at the first page.
## Writing data
```php
$writer = new MyDataWriter(...);
$writer->write($arrayOfItems);
```
## Processing data
```php
$processor = new MyDataProcessor(...);
$processor->process($arrayOfItems);
```
## Documentation
- Guide: [Português - Brasil](docs/guide/pt-BR/README.md)
- [Internals](docs/internals.md)
If you need help or have a question, the [Yii Forum](https://forum.yiiframework.com/c/yii-3-0/63) is a good place for
that. You may also check out other [Yii Community Resources](https://www.yiiframework.com/community).
## License
The Yii Data is free software. It is released under the terms of the BSD License.
Please see [`LICENSE`](./LICENSE.md) for more information.
Maintained by [Yii Software](https://www.yiiframework.com/).
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