I am new to Beego as well as Go. I read its documentation but it puts every ORM operation in the main package instead of model package. I can't understand how to organize the code. I am really very confused.
You can feel free to follow steps as below, and try to build your first database program.
Build [Models]
According to the table structure of your database.
Initialize the ORM
New an ORM instance
Operate CRUD as your want
Link:
Guidance for Beego/orm configuration
https://beego.me/docs/mvc/model/orm.md
Guidance for operating CRUD on Beego/orm
https://beego.me/docs/mvc/model/object.md
Related
I'm working on a simple task of adding a new table to an existing SQL DB and wiring it into a SpringBoot API with SpringData.
I would typically start by defining the DB table directly, creating PK and FK, etc and then creating the Java bean that represents it, but am curious about using the SpringData initialization feature.
I am wondering when and where Spring Data + JPAs schema generation and DB initialization may be useful. There are many tutorials on how it can be implemented, but when and why are not as clear to me.
For example:
Should I convert my existing lower environment DBs (hand coded) to initialized automatically? If so, by dropping the existing tables and allowing the App to execute DDL?
Should this feature be relied on at all in production envrionment?
Should generation or initialization be run only once? Some tutorial mention this process running continually, but why would you choose to lose data that often?
What is the purpose of the drop-and-create jpa action? Why would
you ever want to drop tables? How are things like UAT test data handled?
My two cents on these topics:
Most people may say that you should not rely on automated database creation because it is a core concept of your application and you might want to take over the task so that you can lnowmfor sure what is really happening. I tend to agree with them. Unless it is a POC os something not production critical, I would prefer to define the database details myself.
In my opinion no.
This might be ok on environments that are non-productive. Or on early and exploratory developments. Definetely not on production.
On a POC or on early and exploratory developments this is ok. In any other case I see this being useful. Test data might also be part of the initial setup of the database. Spring allows you to do that by defining an SQL script inserting data to the database on startup.
Bottomline in my opinion you should not rely on this feature on Production. Instead you might want to take a look at liquibase or flyway (nice article comparing both https://dzone.com/articles/flyway-vs-liquibase), which are fully fledged database migration tools on which you can rely even on production.
My opinion in short:
No, don't rely on Auto DDL. It can be a handy feature in development but should never be used in production. And be careful, it will change your database whenever you change something on your entities.
But, and this is why I answer, there is a possibility to have hibernate write the SQL in a file instead of executing it. This gives you the ability to make use of the feature but still control how your database is changed. I frequently use this to generate scripts I then use as blueprint for my own liquibase migration scripts.
This way you can initially implement an entity in the code and run the application, which generates the hibernate sql file containing the create table statement for your newly added entity. Now you don't have to write all those column names and types for the database table yourself.
To achieve this, add following properties to your application.properties:
spring.jpa.hibernate.ddl-auto=none
spring.jpa.properties.javax.persistence.schema-generation.scripts.create-target=build/generated_scripts/hibernate_schema.sql
spring.jpa.properties.javax.persistence.schema-generation.scripts.action=create
This will generate the SQL script in your project folder within build/generated_scripts/hibernate_schema.sql
I know this is not exactly what you were asking for but I thought this could be a nice hint on how to use Auto DDL in a safer way.
I am a web designer with no coding experience . I was offered a project. .. the client wants a "tool to put all his data(huge employee records) on cloud and to access it as needed " .My question is
What exactly such a tool is called ?
Can it be built without coding? Websites like joomla, etc. Can they be used somehow ?
Can coding be learnt simultaneously with the project?
Sorry for the silly question.
We need a little more information. Is the employee data stored in a database? What type of database is it? When you say cloud what do you mean? AWS?
You might be able to create SQL queries without learning SQL using tools like mysqlworkbench but what you would do with that data after the query I'm not sure.
I using JPA and MySQL in Spring boot. Howto make a initial content data of database?
Example, need create the basic sections, default admin user, etc.
Thanks.
I would recommend that you take a look at Flyweight, It is nicely integrated into SpringBoot.
We use it to create the initial database, and for adding new tables or modifying the database when deploying new version of our application.
I would recommend that you create a script /resources/db/migration/V1__Initial.sql Which just have the table layout and then a V2__data.sql with the initial data.
A script can only be run once, and you can't modify it after it has been run, this information is stored in a table named schema_version, which you will probably have to delete, or manipulate during development. Here is a link
to how it works - These days I would never do a real world project without using it.
I'm trying to learn martini, coming from Rails. What's being used for database migrations in the martini world?
There is no such thing in martini. It is just a helper for writing web services. If you want database migrations, or a database at all, use third-party packages.
An example tool stack would be:
goose for creating migrations
gorp for a database object layer
This or a completely different setup, e.g. using Go's standard database package, can be used with martini.
I have a problem with migrating my SQLite3 database to PostgreSQL. How and what do I need to do?
I am searching the internet, but find only migrations from MySQL to PostgreSQL.
Can anyone help me?
I need to convert my SQLite database to PostgreSQL database for Heroku cloud hosting.
You don't want to try to do a binary conversion.
Instead, rely on exporting the data, then importing it, or use the query language of both and using selects and inserts.
I HIGHLY recommend you look at Sequel. It's a great ORM, that makes switching between DBMs very easy.
Read through the opening page and you'll get the idea. Follow that by reading through the cheat sheet and the rest of the documentation and you'll quickly see how easy and flexible it is to use.
Read about migrations in Sequel. They're akin to migrations in Rails, and make it very easy to develop a schema and maintain it across various systems.
Sequel makes it easy to open and read the SQLite3 table, and concurrently open a PostgreSQL database and write to it. For instance, this is a slightly modified version of the first two lines of the "cheat sheet":
SQLITE_DB = Sequel.sqlite('my_blog.db')
PGSQL_DB = Sequel.connect('postgres://user:password#localhost/my_db')
Base all your subsequent interactions with either database using SQLITE_DB and PGSQL_DB and you'll be on your way to porting the data.
The author of Sequel is very responsive and is a big fan of PostgreSQL, so the ORM has great integration with all its features.