daos | DAOS Storage Stack ( client libraries | Storage library

I have an app with plenty of data, with a switch button, which switch the language (french or english) of the entire app. However, some of my data are stored in a Room database. I have two .db files : database_fr.db and database_en.db.

Let's say the app is currently in french, with the database_fr.db loaded. When the switch button is pressed, I want the app to use the other .db file, to display all the data in english.

I followed this codelab to get familiar with Room, so this is how I loaded the database :

I am writing a Java application following the MVC pattern, abstract enough to allow the backend to connect to an Sql and a NoSql database. I have 4 model classes and 4 DAO interfaces. Each DAO is implemented in two ways, one for sql and one for mongodb. I want to add a Transaction Manager to execute database operations in atomic transactions: the problem is that these operations involve a variable number of DAOs and I don't know how to implement the Manager with more than one Dao. I'm not using Spring and I'm not willing to add it.

I've had the following ideas but each one has something I'm not sure about:

• Make interfaces `MyDao_X` extend another interface `GenericDao` and use the last one in TransactionCode. This way I wouldn't know which Dao to instantiate in `TransactionManagerMysql`
• Extend Function to be an N-Function which can accept N inputs and produce an output. In this case N = 4, so I could always instantiate all the DAOs. Here the doubts are the following: I don't know how to do and I'm following TDD so I should figure out how to test this extension. Moreover, it doesn't seem very efficient to me to instantiate 4 Dao every time just because I don't know how many or the type I need. Additionally, if the number of Dao changes over time, I would be forced to modify all the functions in Service Layer to adapt the number of inputs to lambdas

Here's advice

We are using the jooq codegen plugin to produce dao and pojo classes for one of the MySQL databases. The configuration is as follows:

I have difficulties with generics in Kotlin. I want to make universal interface and implementation and several type-specific DAOs.

I got seemingly trivial use-case, and still I cannot figure it out. Let's take a look at the package structure.

We have two products: Product A and Product B and both have different rest controllers. Both of these controllers are calling the same common service and the common service calling the common dao methods. I want to select the schema in the common daos methods based on which products the call has been made. So for example, if the call is coming from the Product A controller then select schema as A or else B.

I wanted to use the same database connection and change the schema based on which controller the call is made. One possible solution would be to pass the schema name from the controller layer to the service layer which in turn passes it to the dao layer. I want to avoid having two different data sources and then switching between them dynamically.

So is there any other better way that we could do this?

Note: We are using Mybatis as our persistence layer.

Please find the sample code :

Controller for ProductA

I have designed an erc20 token and a smart contract to transfer that token, but when I trigger the function to transfer, the remix told me the following graph.

What I did was to deploy the token smart contract and then the DAO smart contract, then call the creatSubDAO function to start the transfer.

The relative code is below:

So I have this code in

PersoanaDao