fyp/logic/models/classes/main.go

package model_classes

import (
	"database/sql"
	"errors"
	// . "git.andr3h3nriqu3s.com/andr3/fyp/logic/utils"
)

type ModelClass struct {
	Id       string
	ModelId string
	Name     string
}

func ListClasses(db *sql.DB, model_id string) (cls []ModelClass, err error) {
    
    rows, err := db.Query("select id, model_id, name from model_classes where model_id=$1", model_id)
    if err != nil {
        return
    }
    defer rows.Close()

    for rows.Next() {
        var model ModelClass
        err = rows.Scan(&model.Id, &model.ModelId, &model.Name)
        if err != nil {
            return
        }

        cls = append(cls, model)
    }

    return
}

func ModelHasDataPoints(db *sql.DB, model_id string) (result bool, err error) {
    result = false
    rows, err := db.Query("select mdp.id from model_data_point as mdp join model_classes as mc on mc.id = mdp.class_id where mc.model_id = $1 limit 1;", model_id)
    if err != nil {
        return
    }
    defer rows.Close()
    
    return rows.Next(), nil
}

var ClassAlreadyExists = errors.New("Class aready exists")

func CreateClass(db *sql.DB, model_id string, name string) (id string, err error) {
    id = ""
    rows, err := db.Query("select id from model_classes where model_id=$1 and name=$2;", model_id, name)
    if err != nil {
        return
    }
    defer rows.Close()

    if rows.Next() {
        return id, ClassAlreadyExists
    }

    _, err = db.Exec("insert into model_classes (model_id, name) values ($1, $2)", model_id, name)

    if err != nil {
        return
    }

    rows, err = db.Query("select id from model_classes where model_id=$1 and name=$2;", model_id, name)
    if err != nil {
        return
    }
    defer rows.Close()

    if !rows.Next() {
        return id, errors.New("Something wrong")
    }

    if err = rows.Scan(&id); err != nil {
        return
    }

    return 
}