How can I associate two entities, each in a different database.
I have created two entity manager one for each database, default and customer_1.
You cannot associate entities in different databases, at least not in the latest Doctrine version.
Moreover this is not advisable as the underlying database server (ie. MySQL) will not be able to guarantee data integrity across independent databases. Foreign keys for example do not allow you to reference keys outside the parent database.
The multiple entity managers as envisioned by Symfony here http://symfony.com/doc/current/cookbook/doctrine/multiple_entity_managers.html are meant only for accessing different bundle sets in the same app. If you want to associate your entities you'll have to use one database.
Related
I have an AppSync app defined using a master CloudFormation stack and more than a dozen nested stacks. Each nested stack defines a DynamoDB table, an AppSync DataSource for that table, and an IAM role for that DataSource to access that table. The DataSource depends on the role, which depends on the table.
I would like to consolidate these IAM roles, for three reasons:
The role definitions are very repetitive and boilerplate-y.
There are many copies of this app, and it adds up to a lot of IAM roles — enough that we're running close to the soft limits.
Some resolvers use DynamoDB batch operations to access multiple tables, so at least some of the IAM roles must grant access to multiple tables anyway.
I do not want to give the role blanket access to all DynamoDB tables in the account.
The simplest way to grant one role access to every required table would be to list them manually in the policy document. This has the obvious downside of requiring that the policy be manually kept in sync when new tables are added. However, there is also a dependency problem: the DataSource in a nested stack depends on a role in the master stack, which depends on tables in the nested stacks.
I would have liked to use tags: grant for all DynamoDB tables that have a certain tag, then set that tag for each table. This way, the IAM role would not need to be edited when a new table was added. But apparently DynamoDB does not support tag-based conditions.
Is there an easy way to grant a single IAM role access to many DynamoDB tables without granting access to all of DynamoDB and without individually listing the tables in the role?
If you can name your tables in a way that gives them the same prefix you can use wildcards in the resource.
arn:aws:dynamodb:<Region>:<Account>:table/MyPrefix-*
That will work on all tables that start with MyPrefix-
If you are using generated names you can probably use the AWS::StackName value in place of MyPrefix but be aware that with nested stacks that value may get shortened.
I am planning to make a software (ASP.NET 4.6.1 MVC with Entity Framework), which does a lot of reading from DB. Therefor I have one database, which contains all global information, projects etc. and now I am thinking to either bring all the content into the same DB but in different tables or to create a DB for each bigger group.
Now as there is a lot of reading going on, is it bad practise to have the connection information in the main db and then to connect to a different DB? Otherwise I would have the project information in the primary database and the content in a different table on the same DB.
Are there any notable delays to connect to a different DB to retrive the information?
If it's all your data, for your application, it should all go in the same database. Definitely use different tables. You should read up on entity design and normalization... and if you really need to do that, you may already be in over your head.
I want to create a new project on contract management system. In this I have to manage multiple organizations and want to create new instance in sql server dynamically for each organization in a saas environment. How is this posiible? I am using asp.net for development. Any help would be appreciated.
A true SaaS application has a single application and database. It has the ability to have multiple tenants use the application. All data in the database needs to know what tenant it belongs too.
For instance if you have a booking system: Your customers sign up to use the software and become a row in the customer table with an ID. When a booking is made it has a customerID column as a foreign key to the customer table. Then all reports, booking views etc are done for that tenant using their customer id. You as a service provider can then run reports on all customers/tenants for your own purposes. Multiple tenants can use the system and all their data be in the same set of tables. This then means when you need to cluster replicate backup etc it is a single db, and a single migration for schema updates.
See these wiki's on multitenancy and SaaS
This of course requires your DB schema (and your app) to support this - if you are unable to change the schema then there are a number of options to up a new DB based upon the technology you are using. If you are using code first EF, then there will be db creation and migration scripts you can use. Otherwise it may justhave to be a sql script you have to generate and then maintain and run this each time a new customer is required. Personally i would rather have a single DB with an appropriate schema.
I have 2 questions.
I am developing a ASP.NET web application that uses the standard ASP.NET membership. We intend to have the membership tables in 1 database. We have 2 other databases that stores data for 2 different applications.
Shared - Membership info
DB1 - Application1
DB2 - Application2
Both applications uses the membership info in the "Shared" database.
The Shared database has a table called userdetals that will store additional users' info such as name, phone and job title for example.
However, DB1 also has a table called employees that store the same fields as name, phone and job title. Each employee may be an user.
Also for each table in DB1 and DB2, we keep audit trial, i.e. which user updated the tables in the database. Hence, we need to store UserID in the tables of DB1 and DB2.
We thought of having a Users table added in DB1 and DB2. So everytime a new user is created in Shared, the same user will be created in Users table in DB1 and DB2.
Our questions are:
What is the best way to maintain database integrity given the above setup? E.g. Each employee is assigned as an user. If any fields in DB1 such as username, name and phone is updated, then the same fields in Shared DB should be updated and vice versa.
Is it advisable to have membership database in a different database in our case? What is the best solution since almost all the tables in DB1 and DB2 references userID in the Shared database.
1.
The technology you are looking for is Merge Replication (http://bit.ly/KUtkPl). Essentially, you would create a common Users table on both databases, create a Merge Replication publisher on one application database, and then create a Merge Replication subscriber on the other application database. You could also set this up to synchronize the schema as well (which also means you only need to create the table once on the publishing database: it will push the table, schema with data, to the subscriber).
But if you are looking for more of a manual approach, I would not denormalize the user data to the employee(s) table, instead create a supplemental table and a view on each Application server. Kind of like inheritance in OOP: Any common data between the Employee table and Users table, leave on the shared user table. Any unique columns for the Employee, add to the supplemental table only and store on each database. The view would merge both the supplemental table and shared table. (http://bit.ly/9KPxt0)
Even if you do use Replication Services, I would still use this view design with the synchronized table.
You COULD update through the view, but I would not recommend that. It has been done before successfully in production, but there are too many constraints that could blow up (http://bit.ly/LJCJev). Instead update the table directly that holds the data.
Absolutely avoid "triggers that synchronize". Too risky (can cause an infant loop on your SQL server) and too much maintenance overhead.
2.
I would do the Merge Replication, it is just less for you to worry about and maintain after it is configured correctly. But your approach is OK if want something more manual or if you are not familiar with Replication services in SQL... just use the view noted above and you'll be set.
Easy way:
You can create link server to these databases.
And then create synonym to easy access to tables of each database.
Create trigger to update data when any data was updated on each table.
Is it better to extend my business database with the tables of the ASP.NET Membership Security model. Or should I have a different datastore where I only manage Identities and Roles... Basically 1 or 2 databases?
This can depend on scale. If it's an enterprise solution with different apps sharing one membership source the answer is simple - separate them. There might also be performance reasons why you would want to separate this data from the rest of the app. Arguably these tables do not belong in a data warehouse for example.
The only thing the 2 databases solution doesn't give you is referential integrity. If you extend your membership tables to hold more application specific details about the user, and these tables need to link into the main database then you might want to keep them together. Otherwise you would need some sort of replication job maintaining this for you.
This is quite subjective, but unless those users are going to be using more than one database, then I'd say keep them in the same db.
I would only use a separate database for users and roles if those users and roles were used in more than one database.
So no, I'd never use two. I might however use three.
Which database platform are you using? If one that supports schemas within a database, e.g. SQL Server 2008, then you can put your membership tables into their own schema, for neatness. You can also add cross-schema foreign keys if required.