Room entity depends on itself (Relation annotation)
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I have a question about the room and relations.
I know how to link entity to itself (using foreignkey but I cannot retrieve all those data with all dependencies and relations.
@Entity(tableName = "a",
foreignKeys = [
ForeignKey(entity = A::class, parentColumns = ["id"], childColumns = ["parent_id"], onDelete = CASCADE)
])
data class A(@PrimaryKey val id:Long?, val parentId:Long?)
And now I want to fetch all data (parent and its children) so I've created class with Relation annotation:
data class B(
@Embedded var parent:A?,
@Relation(entity = "A::class, parentColumn = "id", entityColumn = "parent_id") var childred: List<B>?
)
I want to achieve some kind of a chain where every child could be a parent for another children but a problem occurs when class B has a list type of B.
Do you know how can I solve this?
Or maybe I did something wrong with relations?
** I know that class A has only id and parent_id but this is just an example. And the same class B may have another relations like class C, D, etc.
android android-sqlite android-room asked Nov 19 at 13:30
EzYy
62
add a comment |
up vote
0
down vote
favorite
I have a question about the room and relations.
I know how to link entity to itself (using foreignkey but I cannot retrieve all those data with all dependencies and relations.
@Entity(tableName = "a",
foreignKeys = [
ForeignKey(entity = A::class, parentColumns = ["id"], childColumns = ["parent_id"], onDelete = CASCADE)
])
data class A(@PrimaryKey val id:Long?, val parentId:Long?)
And now I want to fetch all data (parent and its children) so I've created class with Relation annotation:
data class B(
@Embedded var parent:A?,
@Relation(entity = "A::class, parentColumn = "id", entityColumn = "parent_id") var childred: List<B>?
)
I want to achieve some kind of a chain where every child could be a parent for another children but a problem occurs when class B has a list type of B.
Do you know how can I solve this?
Or maybe I did something wrong with relations?
** I know that class A has only id and parent_id but this is just an example. And the same class B may have another relations like class C, D, etc.
android android-sqlite android-room asked Nov 19 at 13:30
EzYy
62
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I have a question about the room and relations.
I know how to link entity to itself (using foreignkey but I cannot retrieve all those data with all dependencies and relations.
@Entity(tableName = "a",
foreignKeys = [
ForeignKey(entity = A::class, parentColumns = ["id"], childColumns = ["parent_id"], onDelete = CASCADE)
])
data class A(@PrimaryKey val id:Long?, val parentId:Long?)
And now I want to fetch all data (parent and its children) so I've created class with Relation annotation:
data class B(
@Embedded var parent:A?,
@Relation(entity = "A::class, parentColumn = "id", entityColumn = "parent_id") var childred: List<B>?
)
I want to achieve some kind of a chain where every child could be a parent for another children but a problem occurs when class B has a list type of B.
Do you know how can I solve this?
Or maybe I did something wrong with relations?
** I know that class A has only id and parent_id but this is just an example. And the same class B may have another relations like class C, D, etc.
android android-sqlite android-room asked Nov 19 at 13:30
EzYy
62
I have a question about the room and relations.
I know how to link entity to itself (using foreignkey but I cannot retrieve all those data with all dependencies and relations.
@Entity(tableName = "a",
foreignKeys = [
ForeignKey(entity = A::class, parentColumns = ["id"], childColumns = ["parent_id"], onDelete = CASCADE)
])
data class A(@PrimaryKey val id:Long?, val parentId:Long?)
And now I want to fetch all data (parent and its children) so I've created class with Relation annotation:
data class B(
@Embedded var parent:A?,
@Relation(entity = "A::class, parentColumn = "id", entityColumn = "parent_id") var childred: List<B>?
)
I want to achieve some kind of a chain where every child could be a parent for another children but a problem occurs when class B has a list type of B.
Do you know how can I solve this?
Or maybe I did something wrong with relations?
** I know that class A has only id and parent_id but this is just an example. And the same class B may have another relations like class C, D, etc.
android android-sqlite android-room android android-sqlite android-room asked Nov 19 at 13:30
EzYy
62
asked Nov 19 at 13:30
EzYy
62
asked Nov 19 at 13:30
EzYy
62
asked Nov 19 at 13:30
EzYy
62
asked Nov 19 at 13:30
EzYy
62
62
add a comment |
add a comment |
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