com.j256.ormlite.field

Annotation Type ForeignCollectionField

@Target(value=FIELD)
 @Retention(value=RUNTIME)
public @interface ForeignCollectionField

Annotation that identifies a ForeignCollection field in a class that corresponds to objects in a foreign table that match the foreign-id of the current class.

 @ForeignCollection(id = true)
 private ForeignCollection<Order> orders;
 

Author:

graywatson

Field Summary

Fields

Modifier and Type	Fields and Description
static int	DEFAULT_MAX_EAGER_LEVEL

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String	columnName The name of the column.
boolean	eager Set to true if the collection is a an eager collection where all of the results should be retrieved when the parent object is retrieved.
String	foreignFieldName Name of the _field_ (not the column name) in the class that the collection is holding that corresponds to the entity which holds the collection.
int	maxEagerLevel Set this to be the number of times to expand an eager foreign collection's foreign collection.
boolean	orderAscending If an order column has been defined with orderColumnName(), this sets the order as ascending (true, the default) or descending (false).
String	orderColumnName The name of the column in the object that we should order by.

Field Detail

DEFAULT_MAX_EAGER_LEVEL

public static final int DEFAULT_MAX_EAGER_LEVEL

See Also:

maxEagerLevel()

Element Detail

eager

public abstract boolean eager

Set to true if the collection is a an eager collection where all of the results should be retrieved when the parent object is retrieved. Default is false (lazy) when the results will not be retrieved until you ask for the iterator from the collection.

NOTE: If this is false (i.e. we have a lazy collection) then a connection is held open to the database as you iterate through the collection. This means that you need to make sure it is closed when you finish. See LazyForeignCollection.iterator() for more information.

WARNING: By default, if you have eager collections of objects that themselves have eager collections, the inner collection will be created as lazy for performance reasons. If you need change this see the maxEagerLevel() setting below.

Default:

false

maxEagerLevel

public abstract int maxEagerLevel

Set this to be the number of times to expand an eager foreign collection's foreign collection. If you query for A and it has an eager foreign-collection of field B which has an eager foreign-collection of field C ..., then a lot of database operations are going to happen whenever you query for A. By default this value is 1 meaning that if you query for A, the collection of B will be eager fetched but each of the B objects will have a lazy collection instead of an eager collection of C. It should be increased only if you know what you are doing.

Default:

1

columnName

public abstract String columnName

The name of the column. This is only used when you want to match the string passed to Dao.getEmptyForeignCollection(String) or when you want to specify it in QueryBuilder.selectColumns(String...).

Default:

""

orderColumnName

public abstract String orderColumnName

The name of the column in the object that we should order by.

Default:

""

orderAscending

public abstract boolean orderAscending

If an order column has been defined with orderColumnName(), this sets the order as ascending (true, the default) or descending (false).

Default:

true

foreignFieldName

public abstract String foreignFieldName

Name of the _field_ (not the column name) in the class that the collection is holding that corresponds to the entity which holds the collection. This is needed if there are two foreign fields in the class in the collection (such as a tree structure) and you want to identify which column identifies the "owner" of the foreign class. This should be a field with the same type as the one which has the collection.

WARNING: Due to some internal complexities, this it field/member name in the class and _not_ the column-name.

Default:

""