Delete Relation using condition¶
The API deletes objects from a relationship with their parent. The objects are identified implicitly through a whereClause
condition.
Backendless.Data.of( "TABLE-NAME" ).deleteRelation(
parentObject,
relationColumnName,
whereClause )
.then( function( count ) {
})
.catch( function( error ) {
});
Backendless.Data.of( DataTypeX ).deleteRelation(
parentObject,
relationColumnName,
whereClause )
.then( function( count ) {
})
.catch( function( error ) {
});
where:
Argument | Description |
---|---|
TABLE-NAME |
Name of the table where the parent object is stored. |
DataTypeX |
Reference to a JS function/class identifying the table. Name of the table must match the name of the function. |
parentObject |
The object for which the relation with the specified children will be deleted. When this argument is a plain JS object (for the "Untyped Objects" approach), it must contain the "objectId" property. |
relationColumnName |
name of the column representing the relation. Relation between the parent object and the objects identified through whereClause for the column in parentObject will be deleted. |
whereClause |
A where clause condition identifying the objects in the child table which will be removed from the relation to the parent object. |
Return Value¶
Number of child objects removed from the relationship.
Example¶
The following request deletes a relation between a Person
object and all the related objects in the related table identified by column "user"
which match the provided query:
name='Joe' or name = 'Frank'
As a result of the operation, all related objects where the name
property is either Joe or Frank will be deleted from the relation.
var parentObject = { objectId:"41230622-DC4D-204F-FF5A-F893A0324800" };
Backendless.Data.of( "Person" ).deleteRelation( parentObject,
"user",
"name = \"Joe\" or name = \"Frank\"" )
.then( function( count ) {
console.log( "relation has been deleted" );
})
.catch( function( error ) {
console.log( "server reported an error - " + error.message );
});
function Person {
// properties of Person defined here
}
var parentObject = // retrieval of the parent object is out of scope of the example
Backendless.Data.of( Person ).deleteRelation( parentObject,
"user",
"name = \"Joe\" or name = \"Frank\"" )
.then( function( count ) {
console.log( "relation has been deleted" );
})
.catch( function( error ) {
console.log( "server reported an error - " + error.message );
});