120 lines
3.4 KiB
Markdown
120 lines
3.4 KiB
Markdown
# ORM (RU)
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Легковесный ORM: поля мапятся в колонки, без сложных связей.
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Есть sync и async версии.
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## Аннотации
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- `@DbEntity(table = "players")` - имя таблицы. По умолчанию snake_case.
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- `@DbColumn(name = "username")` - имя колонки.
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- `@DbColumn(type = "VARCHAR(32)")` - SQL тип для генерации схемы.
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- `@DbColumn(length = 32, unique = true, nullable = false)` - влияет на schema генерацию.
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- `@DbId(autoIncrement = true)` - primary key.
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- `@DbJson` - JSON поле.
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- `@DbTransient` - игнорировать поле.
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## Пример сущности
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```java
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@DbEntity(table = "players")
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public class PlayerModel {
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@DbId(autoIncrement = true)
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private long id;
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@DbColumn(name = "username", nullable = false, unique = true, length = 32)
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private String name;
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@DbColumn
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private int level;
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@DbJson
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private java.util.Map<String, Object> metadata;
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@DbTransient
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private String temp;
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public PlayerModel() {
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}
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}
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```
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## CRUD
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```java
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EntityManager orm = api.orm();
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orm.insert(entity);
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orm.update(entity);
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orm.delete(entity);
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PlayerModel player = orm.findById(PlayerModel.class, 1L);
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List<PlayerModel> all = orm.findAll(PlayerModel.class);
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PlayerModel one = orm.findOneWhere(PlayerModel.class, "level >= ?", java.util.Collections.singletonList(10));
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List<PlayerModel> many = orm.findWhere(PlayerModel.class, "level >= ?", java.util.Collections.singletonList(10));
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List<PlayerModel> paged = orm.findWhere(PlayerModel.class, "level >= ?", java.util.Collections.singletonList(10), "level DESC", 10, 0);
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long count = orm.count(PlayerModel.class, "level >= ?", java.util.Collections.singletonList(10));
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boolean exists = orm.exists(PlayerModel.class, "username = ?", java.util.Collections.singletonList("Steve"));
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int deleted = orm.deleteWhere(PlayerModel.class, "level < ?", java.util.Collections.singletonList(1));
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```
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## Query Builder
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```java
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EntityManager orm = api.orm();
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List<PlayerModel> top = orm.query(PlayerModel.class)
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.where("level >= ?", 10)
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.orderBy("level DESC")
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.limit(10)
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.list();
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boolean exists = orm.query(PlayerModel.class)
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.where("username = ?", "Steve")
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.exists();
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```
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## Fluent Conditions
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```java
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import static com.andrewkydev.database.orm.Conditions.*;
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List<PlayerModel> players = orm.query(PlayerModel.class)
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.where(eq("status", "ACTIVE").and(gt("level", 10)))
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.list();
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```
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## Join, Group By, Having
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```java
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List<PlayerModel> rows = orm.query(PlayerModel.class)
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.select("players.*")
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.join("LEFT JOIN clans ON clans.id = players.clan_id")
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.groupBy("players.id")
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.having("COUNT(clans.id) > ?", 0)
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.list();
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```
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Если выбрать часть колонок, маппятся только они, остальные остаются дефолтными.
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## Auto ID
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Если `@DbId(autoIncrement = true)` и id пустой (0/null),
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`insert()` получает generated keys и прописывает id в объект.
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## Type Adapters
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UUID уже поддержан. Для других типов:
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```java
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orm.registerAdapter(SomeType.class, new TypeAdapter<SomeType>() {
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@Override
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public Object toDatabase(SomeType value) {
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return value == null ? null : value.toString();
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}
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@Override
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public SomeType fromDatabase(Object value) {
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return value == null ? null : SomeType.parse(value.toString());
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}
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});
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```
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