Join (Carbonado 1.2.3 API)

+
+
+
```
@Documented
+@Retention(value=RUNTIME)
+@Target(value=METHOD)
+public @interface Join
```
+
Identifies a Storable property as defining a join relationship + with another Storable type. Joins can also refer to their own enclosing + class or interface. +
+ To complete the join, lists of internal and external properties may be + supplied. If these lists are not supplied, then join is "natural", and the + properties are determined automatically. When the lists are specified, the + join is "explicit". Natural joins are merely a convenience; they can always + be replaced by an explicit join. +
+ The lists used for explicit joins must have the same length, and each must + have at least one element. Each element in the internal list must refer to + a property defined in this property's class or interface, and each element + in the external list must refer to a matching property defined in the joined + type. The matched up property pairs must not themselves be join properties, + and they must be compatible with each other. +
+ If the join is made to external properties which do not completely specify a + primary key, then the type of the join property must be a Query of + the joined type. When the type is a Query, a property mutator method cannot + be defined. The returned query has all of the "with" parameters filled in. +
+ With a natural join, the internal and external properties are deduced by + examining the type of the referenced join property. If the type is a Query, + then the internal and external properties are set to match this property's + primary key. The referenced join property (specified as a parameterized type + to Query) must have properties matching name and type of this property's + primary key. +
+ If a natural join's property type is not defined by a Query, then the + internal and external properties are set to match the referenced property's + primary key. This join property must have properties matching name and type + of the referenced property's primary key. + +
Example:
```
+ @PrimaryKey("addressID")
+ public interface Address extends Storable {
+     int getAddressID();
+
+     ...
+ }
+
+ @PrimaryKey("userID")
+ public interface UserInfo extends Storable {
+     int getUserID();
+     void setUserID(int id);
+
+     int getAddressID();
+     void setAddressID(int value);
+
+     // Natural join, which works because Address has a primary key
+     // property of addressID which matches a property in this type.
+     @Join
+     Address getAddress() throws FetchException;
+     void setAddress(Address address);
+
+     // Explicit join, equivalent to getAddress.
+     @Join(internal="addressID", external="addressID")
+     Address getCurrentAddress() throws FetchException;
+     void setCurrentAddress(Address address);
+
+     @Nullable
+     Integer getParentID();
+     void setParentID(Integer value);
+
+     // Many-to-one relationship
+     @Nullable
+     @Join(internal="parentID", external="userID")
+     UserInfo getParent() throws FetchException;
+     void setParent(UserInfo parent);
+
+     // One-to-many relationship
+     @Join(internal="userID", external="parentID")
+     Query<UserInfo> getChildren() throws FetchException;
+
+     ...
+ }
+ 
```
+
Author:
+
Brian S O'Neill
+

+ +

Optional Element Summary

+ + + + + + + + + + + + + + +

Optional Elements
Modifier and Type	Optional Element and Description
`java.lang.String[]`	`external` + List of property names defined in the foreign property's enclosing class + or interface. +
`java.lang.String[]`	`internal` + List of property names defined in this property's enclosing class or + interface. +

+ +
- + + +
  Element Detail
  + + + +
  - +
    internal
    +
```
public abstract java.lang.String[] internal
```
    +
    List of property names defined in this property's enclosing class or + interface.
    +
    +
    Default:
    +
    {}
    +
    +
  + + + +
  - +
    external
    +
```
public abstract java.lang.String[] external
```
    +
    List of property names defined in the foreign property's enclosing class + or interface.
    +
    +
    Default:
    +
    {}
    +
    +
  +
+

Annotation Type Join

Optional Element Summary

Element Detail

internal

external