How to use model with multiple identical tables, for data isolation? - class

I am writing a simple SaaS application for small construction companies to use and am trying to achieve mid-level data isolation by having each company have their own unique data tables that aren't shared.
This is also nice in case the WHERE {group_id} clause is missing, other group data won't be exposed.
I am able to use the command builder to create these tables dynamically, prefixing them with the group number like grp_37645_projects.
But I am stuck on how to use my model classes as the table names change.
After login, I want to set the table names. These won't change as users aren't allowed to be a part of more than one group.
I have read about changing the tableName, but that is a STATIC function, and I have read a little about creating classes on the fly, but neither option was detailed or complete.
I also know this touches on the single table inheritance, but once again, every example use a little different scenario.
Do you have a recommended solution for setting the tableNames dynamically?

Add some logic for tableName:
namespace app\models;
use yii\db\ActiveRecord;
class Project extends ActiveRecord
{
/**
* #return string the name of the table associated with this ActiveRecord class.
*/
public static function tableName()
{
//some logic for getting current "group_id" for current user
$current_group_id = \Yii::$app->user->identity->group_id;
return 'grp_'.$current_group_id.'_projects';
}
}

Related

Call to undefined method Illuminate\Database\Query\Builder::with() when retrieving orders with providers and services

I am trying to retrieve orders with their service names and provider names all which are in a many to many relationship.
Additionally, I want to use joins to get the client, name.
I have thus used the code bellow
$orders = DB::table('orders')
->join('users', 'orders.user', 'users.id')
->select('users.name As client', 'orders.id', 'orders.amount As amount','orders.description As description', 'orders.status As status')
->with('providers')
->with('services')
->where(['orders.status'=>1])
->get();
In the Order model class, I have implemented the relationships as follows
public function providers()
{
return $this->belongsToMany(ServiceProvider::class)
->as('provider');
}
public function services()
{
return $this->belongsToMany(Service::class)
->as('service');
}
With this I am expecting to retrieve each order with all the services and providers related to it and since I have a foreign key user linking orders to users table, I have used joins to get the name of the user who placed the order as client. Now my problem is that this is not working and is giving the error above. Does this mean that the with() method does not exist in database query builder? if so what method can I use with database query builder to achieve this? Incase there is none, how can I use eloquent ORM to achieve the same purpose?
When you use the DB::table() method, you are not using your Models, so the ->with() method, which is used to include Relationships is not available. To handle this, please use your Models:
$orders = Order::join('users', 'orders.user', 'users.id')
->select('users.name As client', 'orders.id', 'orders.amount As amount','orders.description As description', 'orders.status As status')
->with(['providers', 'services'])
->where('orders.status', 1)
->get();
Additional fixes:
The ->with() method can accept an Array of relationships to include:
->with('providers')->with('services') can be written as ->with(['providers', 'services'])
The where() method can accept an array for multiple where clauses, but is unnecessary for a single where clause:
->where(['orders.status'=>1]) is the same as ->where('orders.status', 1)

How to store polymorphic related models

I am working on a system that have lots of users each has his own information so I needed to create a model for each. On the other hand, all those users have a common user model where their credentials being collected form those requirements it was suitable to have a polymorphic relation between all user types and the user model i.e., coordinator as a model and the user as a model I did the following
class Coordinator extends Model
{
protected $fillable= ['userid', ...];
...
public function user()
{
return $this->morphOne(User::class, 'userable');
}
}
class User extends Model
{
...
public function userable()
{
return $this->morphTo();
}
}
class CreateUsersTable extends Migration
{
public function up()
{
$table->bigIncrements('id');
...
$table->morphs('userable');
}
}
class CreateCoordinatorsTable extends Migration
{
public function up()
{
$table->bigIncrements('coordid');
...
$table->foreign('userid')->references('ID')->on('wp_users')->onDelete('cascade');
}
}
After migration I noticed that columns userable_type and userable_id not allowing null. How come I create a coordinator entity with its associated user entity?
I got it after googling...
Laravel One to Many Polymorphic Relationship - Create Records
The idea is not as I thought at the beginning. When I used the $table->morphs('userable'); the user table had two columns, userable_id and userable_type, and each allows no null by default and by ORM convention and I was thinking that they consider the user table is the master and other tables (i.e., coordinator, educator, shipper etc.) each as the detail table. According to this initial wrong understanding I was adding a userid column at each table to store the related user id for each specific user type and I was wondering how I am going to save the user that needs the userable_id and userable_type to be filled by saving the specific user first to get its id that will be provided to the user's userable_id the case resembles a deadlock situation as each table needs a piece of information that will be known after storing data on each to be able to save data to each table, wired!!!.
However, when I read the article in the above link I figured that it considers the table in an opposite way, unlike my thinking was (i.e., coordinator, shipper, etc. are the masters and the user table is the detail). That is for guys who use the models directly but for those who use repository package it is a little bit tricky and you need to do an extra work...

Eloquent Friendly Column Name

We're currently transitioning from one database to another. A table in our legacy database has column names that are less than ideal, for example:
some_crazy_name__xyz
In our new database, we'd like to have a column name like:
someCrazyName
In the short term, we have to work with data from our legacy database. At some point in the near future, we'd like to switch over without having to refactor all of our Eloquent code to query for different column names. For example:
$model = MyModel::where('someCrazyName', '=', 1);
I'm currently extending the Model class, where all implementing models provide a map of terrible names to friendly names:
class MyModel extends BaseModel {
$columnMap = array(
'someCrazyName' => 'some_crazy_name__xyz'
);
}
This works well where I can use __get and __set in BaseModel to lookup properties in my map, for example:
$myModel = new MyModel;
// ...
echo $myModel->someCrazyName;
However, this obviously doesn't work well with queries without having to always use my map to look up column names. I'm wondering if it's possible without having to override all of the methods within Illuminate\Database\Eloquent\Model, Illuminate\Database\Query\Builder and Illuminate\Database\Eloquent\Builder that deal with columns, where the underlying query that is built always maps to the correct column? Then after we transition databases, we can remove that one piece of code rather then remove potentially thousands of column name mappings.
This is what you need: https://github.com/jarektkaczyk/eloquence/wiki/Mappable
It's not only for mapping badly_named_columns to something_useful, but also can be used for relational mappings:
// simple aliasing
User::where('cool_name', 'value') // where badName = ?
// relations, eg. User hasOne Profile
User::where('first_name', 'Jon') // search through related profiles table
// and obviously mutators:
$user->first_name == $user->profile->first_name
$user->cool_name = 'Jon' // becomes $user->badName = 'value'
$user->cool_name; // 'Jon'
One way to do it would be with accessors.
For example, in MyModel you could define an accessor for the some_crazy_name__xyz column like this:
public function getSomeCrazyNameAttribute()
{
return $this->attributes['some_crazy_name__xyz'];
}
You can then transparently refer to that column with $mymodel->someCrazyName. You can also define a mutator to set the value.
Admittedly, this may not be the best solution if you have MANY values like this. But it does have one important benefit: later on, if you refactor your database so that the column some_crazy_name__xyz is actually called someCrazyName, all you need to do is remove that function from your model. And, to my mind at least, it's simpler than trying to override a bunch of methods on the various classes involved.
And unfortunately, it doesn't adequately address the use of column names in queries. For that, you might want to look at the repository pattern. But in any event, it looks like there's going to be a lot of coding involved.
Finally, you haven't mentioned what database you're using. If it's MySQL, it is possible to create updatable and insertable views. Using a view, you could simply map old column names to new, and point your Eloquent model at the view instead of a table. Other database servers may provide similar functionality.

Entity Framework : map duplicate tables to single entity at runtime?

I have a legacy database with a particular table -- I will call it ItemTable -- that can have billions of rows of data. To overcome database restrictions, we have decided to split the table into "silos" whenever the number of rows reaches 100,000,000. So, ItemTable will exist, then a procedure will run in the middle of the night to check the number of rows. If numberOfRows is > 100,000,000 then silo1_ItemTable will be created. Any Items added to the database from now on will be added to silo1_ItemTable (until it grows to big, then silo2_ItemTable will exist...)
ItemTable and silo1_ItemTable can be mapped to the same Item entity because the table structures are identical, but I am not sure how to set this mapping up at runtime, or how to specify the table name for my queries. All inserts should be added to the latest siloX_ItemTable, and all Reads should be from a specified siloX_ItemTable.
I have a separate siloTracker table that will give me the table name to insert/read the data from, but I am not sure how I can use this with entity framework...
Thoughts?
You could try to use the Entity Inheritance to get this. So you have a base class which has all the fields mapped to ItemTable and then you have descendant classes that inherit from ItemTable entity and is mapped to the silo tables in the db. Every time you create a new silo you create a new entity mapped to that silo table.
[Table("ItemTable")]
public class Item
{
//All the fields in the table goes here
}
[Table("silo1_ItemTable")]
public class Silo1Item : Item
{
}
[Table("silo2_ItemTable")]
public class Silo2Item : Item
{
}
You can find more information on this here
Other option is to create a view that creates a union of all those table and map your entity to that view.
As mentioned in my comment, to solve this problem I am using the SQLQuery method that is exposed by DBSet. Since all my item tables have the exact same schema, I can use the SQLQuery to define my own query and I can pass in the name of the table to the query. Tested on my system and it is working well.
See this link for an explanation of running raw queries with entity framework:
EF raw query documentation
If anyone has a better way to solve my question, please leave a comment.
[UPDATE]
I agree that stored procedures are also a great option, but for some reason my management is very resistant to make any changes to our database. It is easier for me (and our customers) to put the sql in code and acknowledge the fact that there is raw sql. At least I can hide it from the other layers rather easily.
[/UPDATE]
Possible solution for this problem may be using context initialization with DbCompiledModel param:
var builder = new DbModelBuilder(DbModelBuilderVersion.V6_0);
builder.Configurations.Add(new EntityTypeConfiguration<EntityName>());
builder.Entity<EntityName>().ToTable("TableNameDefinedInRuntime");
var dynamicContext = new MyDbContext(builder.Build(context.Database.Connection).Compile());
For some reason in EF6 it fails on second table request, but mapping inside context looks correct on the moment of execution.

Attempting to use EF/Linq to Entities for dynamic querying and CRUD operations

(as advised re-posting this question here... originally posted in msdn forum)
I am striving to write a "generic" routine for some simple CRUD operations using EF/Linq to Entities. I'm working in ASP.NET (C# or VB).
I have looked at:
Getting a reference to a dynamically selected table with "GetObjectByKey" (But I don't want anything from cache. I want data from database. Seems like not what this function is intended for).
CRM Dynamic Entities (here you can pass a tablename string to query) looked like the approach I am looking for but I don't get the idea that this CRM effort is necessarily staying current (?) and/or has much assurance for the future??
I looked at various ways of drilling thru Namespaces/Objects to get to where I could pass a TableName parameter into the oft used query syntax var query = (from c in context.C_Contacts select c); (for example) where somehow I could swap out the "C_Contacts" TEntity depending on which table I want to work with. But not finding a way to do this ??
Slightly over-simplyfing, I just want to be able to pass a tablename parameter and in some cases some associated fieldnames and values (perhaps in a generic object?) to my routine and then let that routine dynamically plug into LINQ to Entity data context/model and do some standard "select all" operations for parameter table or do a delete to parameter table based on a generic record id. I'm trying to avoid calling the various different automatically generated L2E methods based on tablename etc...instead just trying to drill into the data context and ultimately the L2E query syntax for dynamically passed table/field names.
Has anyone found any successful/efficient approaches for doing this? Any ideas, links, examples?
The DbContext object has a generic Set() method. This will give you
from c in context.Set<Contact>() select c
Here's method when starting from a string:
public void Test()
{
dynamic entity = null;
Type type = Type.GetType("Contract");
entity = Activator.CreateInstance(type);
ProcessType(entity);
}
public void ProcessType<TEntity>(TEntity instance)
where TEntity : class
{
var result =
from item in this.Set<TEntity>()
select item;
//do stuff with the result
//passing back to the caller can get more complicated
//but passing it on will be fine ...
}