I'm more used to a PostgreSQL world and am now struggling with Oracle.
I have multiple microservices with Spring Boot which use Flyway for database migration. With PostgreSQL, I would create a "database" for each microservice (e.g. createdb -O microservice1_user microservice1 and createdb -O microservice2_user microservice2) so that the tables don't clash and each microservice has its own flyway_schema_migration` table.
I have now access to one Oracle server. I have administrator access (if I'm not mistaken - I have an owner and a support user account).
What would be the best practice here? Can I create the equivalent of a "databases" (I think they are "schemas" in Oracle? And each schema is also a user?) for each microservice? Do I need to prefix the tables (I really would like to avoid that)?
Thanks!
SCHEMA and USER are practically synonymous in Oracle - so yes, each of your databases could be represented as a SCHEMA in Oracle.
However, if a user is granted privs, it would allow them to see data in another schema.
If you need a harder 'partition' then you could use the multitenant feature in Oracle.
You would then have a separate pluggable database for each microservice. Each could have one or more schemas, but they wouldn't be able to accidentally or otherwise access the data from another pluggable database.
We have customers who have implemented both architectural styles, so there's not necessarily a right or wrong way.
Going with multiple schemas in a single database is obviously the simpler way to go.
Related
We are a team of tens of data analysts. Our main data back-end is an Oracle database. We use personal schemas to do work where we don't need to collaborate with others and we would like to create schemas dedicated to projects where people need to collaborate.
The problem is that in Oracle, one schema is equivalent to one DB user. If we create a schema dedicated to a project, for the purpose of creating DB objects in the context of that project, there will be a single set of credentials (username + password) that needs to be shared by all team members. This has two inconveniences:
if people mistype the credentials, they can block the account for everyone;
it is no longer possible to monitor who did what for security/audit reasons, since everyone uses the same schema;
An alternative would be that only one person uses the Schema user to create objects and assigns privileges to other people in those objects, but that can become quickly cumbersome.
Another alternative is to interact with the DB through R or Python but that means the credentials will be stored in some text file, which is bad for security.
As we see it, the ideal situation is if multiple personal DB users can create objects in the same schema, and if those objects are automatically available for that set of DB users. Is this totally impossible in Oracle? Is this impossible in any major DB? Is this requirement somehow flawed and as such, there is a good reason for why it is not available?
We could compare this collaboration in a DB schema to what commonly happens with people collaborating in a folder, using R, Python or other programming language for data analytics.
Thank you for your advise!
Maybe I miss something but could you not just create a schema that will be used for all users and grant the required privileges to each individual user?
Each user authenticates with his local account and by default uses his local schema and to access the public one you just use the ALTER SESSION SET CURRENT_SCHEMA command.
I need to create interfaces between two different databases. I have an Oracle database and another Postgresql database.
The problem is that the schemas and structures of the databases are different.
I have performed migration / interface processes between two Postgresql databases before, but never with Oracle.
I think it is possible to do it with DBlink.
I need to keep both databases updated (bidirectional).
What do you suggest is a good alternative?
I've been trying for days but cannot find the answer to this. I am using Oracle Application Express (APEX), someone else setup the initial connection to a "Apex" database in oracle, but I am trying to connect to our production database in oracle. I am making web forms and the web forms are connected to the "Apex" database that was setup already, but I need to connect to our production database so we can create reports from the data entered through the web forms. I need the tables to show up in the create page option from the production database, currently its coming from the apex database, please help.
Create Page View with Tables (from apex)
Thank You so much in Advance!
What is the "production database"? Is it really a different database (than the one you're currently connected to), or is it a user in the same database?
if former:
you could create a database link between those two databases and create synonyms for production users' tables in one of schemas your workspace is assigned to.
another option is to install Apex onto the production database, so that you could use current installation as "development" and then deploy the application into the "production-based" Apex
if latter, you might do the same (i.e. create synonyms, just without the database link), or simply assign the production schema to your workspace
You may be interested to read Mike's response to a question with a similar misunderstanding regarding architecture.
https://community.oracle.com/thread/4135843
Once you have your head wrapped around this, you can consider the parsing schema to your application. This schema defines the table access your application has, in the normal way Oracle handles table privileges.
Then it's up to you to define who has access to what pages, using APEX Authorisation Schemes.
I have an ERP application running with Oracle forms and Oracle database. Now I am planning to migrate this application to a java based enterprise application. will it be a good idea to keep the existing oracle database as back end and developing a web application with certain level of changes/additions in the DB design.
There are two facts to know before answer your questions:
has your database schema some oracle forms special structures or is it in 3rd normal form and simply stores data using keys and enforced referential integrity?
How much stored code contains your database?
Ad 1. Oracle forms don't have specific schema reqiurements. They work best if your schema if based on 3rd normal form. If your schema is like this, use it for new Java application. We have both forms and Java EE applications on same database schemas and is works fine.
Advantage is, if you have keys (primary, unique, foreign) in your schema. Use them when generating Java app.
Probably you will have to add #Version columns for optimistic locking (see https://docs.oracle.com/javaee/6/api/javax/persistence/Version.html). But there is not reason to build new schema for it.
Ad 2. Your will have to overwrite bigger part of database stored code (triggers, procedures, functions) to Java. In most cases this does not have dramatic impact to schema structure, but deal with it.
So - if your database schema is not tailored to some UI client needs AND you want only use a new client, use your schema. If not, create a new one.
In my project, I am using Oracle Database and SubSonic for DAL. I have a problem with SubSonic and Oracle Schema, that is:
When developing, I used a schema DEV in Oracle Database and generate DAL using SubSonic.
After that when release to customer, he used a new schema TEST in Oracle Database and changed the connection string in app.config to connect to Oracle. The error will appear, that is “Table or View does not exist”. I found this error and see that the schema of tables is still DEV.
I do not want re-generate DAL after change schema and when released to the customer. Please help me.
Firstly, your schema should not be DEV. DEV is a user or role.
Your schema name should be related to the data content (eg ACCOUNTS or SALES)
Secondly, consider whether you or the customer is going to decide the schema name. Say you have a product called FLINTSTONE. You may decide that the schema name should be FLINTSTONE. However your customer may want to run two instances of your product (eg one for local sales, the other for international) and use the same database. So they want FS_LOCAL and FS_INTER as the schema names. Is that option a feature of your product ?
Next, decide if your application should connect as the schema owner. There are good security reasons for NOT doing that. For example, the schema owner has privileges to drop tables, which is generally something the application doesn't do and thus, on the principle of least privilege, is something your application shouldn't have privileges to do.
Generally I would recommend some config parameter for the application for the schema name, and after connecting to the database, the app should do an "ALTER SESSION SET CURRENT_SCHEMA = 'whatever was it the config file'". The application database user would need the appropriate insert/update/delete/select/execute privileges on the objects in the application schema. If the application can't do that, you can have a LOGON trigger in the database.
Gary is correct in not using DEV as a schema on your own machine. In using Oracle we typically set up the schema as what the client is going to name their schema. This however does not fix your issue. What you need to do is create a global alias in Oracle that maps say DEV to CLIENTSCHEMA. You should still rename the schema on your machine but this will allow your schema to differ from your clients.