relationship

I have two data structures "database" and "components" const DatabaseSchema = mongoose.Schema({ components: [{ type: Schema.Types.ObjectId, ref: 'Components', required: false }], }); const ComponentsSchema = mongoose.Schema({ name: { type: String, required: true, trim: true, unique: true, lowercase: true }, updatedAt: Date, }); I want to filter all items in the database by component names search rule I'm using Database.find({ components: { $elemMatch: { name: /antr/i } } }).populate({ path: 'components', select: 'name -_id' }).select(['descript','components']).exec( (err,data) => { console.log

I am working on a small project where I have to maintain follows between users like twitter. I am trying to make a query that returns the followers of a certain node, let's call it "X" node. So the query returns the followers of "X" and the count of the followers of the followers of "X" and the count of how many nodes the followers of "X" are following, including "X" in that count. Sorry for the wordplay. Let's see an example with images: I have the following nodes: And I want to know all the followers of Node 2 and the counts I mentioned before of its followers. I created the next query:

I have 2 entities. entity 1 - People entity 2 - books People entity has a property which is an array of string names of their favorite books. I need to create a relationship that somehow maps the favorite book of a person to the corresponding book entity object(s). I am not sure how to do this. So far I have started by creating a relationship in core data model for people by setting destination to "books" and then for the books entity creating a relationship by setting destination to "people". I don't see or understand how this will automatically pick out each of the person's favorite books..

I hit an issue when trying to delete records due to FK constraints. I therefore went back to the drawing board and am trying to specify how the relationship should work. Here are my code first classes: public class MemberDataSet { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int Id { get; set; } public int? DeferredDataId { get; set; } [ForeignKey("DeferredDataId")] public virtual DeferredData DeferredData { get; set; } } public class DeferredData { [Key] [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] public int Id { get; set; } //other properties

Does the double line in the following ER diagrams means total participation or recursive relation? Could anyone tell me the notation difference for both? Eric Hotinger Total Participation: Every entity in the set is involved in some association (or tuple) of the relationship. Recursive Relationship: An entity set relating to itself. Most commonly in recursive relationships they indicate the different types of roles an entity can have (e.g., the different ways it can participate) in a relationship by writing each role above each line. An example of this would be in a Course table with a

So, I'm receiving the following error from Laravel framework; but I couldn't find why this framework is producing this error: SQLSTATE[42000]: Syntax error or access violation: 1066 Not unique table/alias: 'participants' (SQL: select `participants`.*, `participants`.`message_id` as `pivot_message_id`, `participants`.`user_id` as `pivot_user_id`, `participants`.`created_at` as `pivot_created_at`, `participants`.`updated_at` as `pivot_updated_at` from `participants` inner join `participants` on `participants`.`id` = `participants`.`user_id` where `participants`.`deleted_at` is null and