I've implemented the AbstractRoutingDataSource in order to horizontally partition my data [1]. I rely on Hibernates functionality to create and update the database schema. This works fine for the first datasource, which is resolved by the determineCurrentLookupKey() declared in AbstractRoutingDataSource.
Is there a way to apply the schema generation/update to the other datasources as well?
I've found the classes SchemaExport and SchemaUpdate respectively, that are capable of the required functionality. However, both require an instance of org.hibernate.boot.MetaData, which I don't how to obtain.
(I'm using Spring Boot in version 1.4.2.RELEASE.)
[1] https://spring.io/blog/2007/01/23/dynamic-datasource-routing/
Thanks!
I got the same issue and found a solution using the SchemaExport class of hibernate.
For each DataSourceEnum you can manually initialize the datasource.
here is my detailed answer to my own issue discription
Related
I created user in oracle database and I am trying to create session but I find many ways in spring boot so what is the easy way if I want to create classe connections using the Username and Password ?
You can jdbc template, spring data JDBC or spring data JPA, well depending on your use case.
If your data model is quite complex, you should avoid using the JDBC template as you will need to write prepared statements which can be cumbersome. JPA will allow you to use object-oriented programming principles and also will help you map the entities to your database columns.
For example, if you are going to use spring data JPA, you need to set the application properties as follows:
spring.datasource.type=oracle.oracleucp.jdbc.UCPDataSource
spring.datasource.oracleucp.connection-factory-class-name=oracle.jdbc.pool.OracleDataSource
spring.datasource.oracleucp.sql-for-validate-connection=select * from dual
spring.datasource.oracleucp.connection-pool-name=UcpPoolBooks
spring.datasource.oracleucp.initial-pool-size=5
spring.datasource.oracleucp.min-pool-size=5
spring.datasource.oracleucp.max-pool-size=10
This would behind the scene create an Oracle Datasource. In this example, we are using Oracle Universal Connection Pooling. You can also use HikariCP which is quite popular.
check this out
If you want to use UCP with above properties then you must have SpringBoot version higher than 2.4.0.
Check out the Spring Boot code sample on GitHub.
I am writing a Spring Batch job and don't care about restarts and don't want the hassle of creating, securing and managing an Oracle schema for Spring Batch database objects. H2 on the file system is more than enough for us.
The issue is that I am writing an batch job that needs to connect to an Oracle database and failing miserably just trying to get 2 data sources, transaction managers and entity managers. Right now I am trying two H2 database and haven't even tried configuring Oracle database yet.
I have used two Oracle data sources in other Spring Boot applications successfully in the past but this is my first attempt with Spring Batch that has configuration code to create the data source.
I have tried creating two DataSource, EntityManagerFactoryBean and TransactionManager with one using default spring.datasources configuration, default bean names and #Primary.
I have tried creating just a second DataSource, EntityManagerFactoryBean and TransactionManager with different bean names. This seems to have an issue that the TransactionManager orEntityManager is already assigned to the thread.
I have tried creating a dataSource for batch but run into circular bean creation errors.
I have tried creating a BatchConfigurer and that runs into circular bean creation errors.
I have tried creating a JobRepositoryFactoryBean but a default one is still created.
I have tried using a #PersistenceContext on my #Entity classes.
It shouldn't be this hard so I must be missing something. Any help would be appreciated.
Thanks, Wes.
I think I have some success. I am able to eventually run the batch job using Spring Boot 2.2.0 and Spring Batch 4.2.0 but I have to wait for a 5 minute timeout while creating the Entity Manager for H2 for the Spring Batch repository. The Oracle Entity Manager is registered really quickly and before the H2 Entity Manager despite the H2 Entity Manager being #Primary.
I have a separate configuration class for each of my two DataSources. Each one is annotated with #Configuration, #EnableTransactionManagement and #EnableJPARepository.
The one for Spring Batch is using the standard bean names, dataSource, entityManagerFactory and transactionManager. Each #Bean is annotated with #Primary.
One setting that I needed was to add a .packages("org") to the entityManagerFactory bean. This would pick up all of org.springframework including Spring Batch.
The only other real change I have made from common implementations is to set the dialect in the JPA Properties of the Entity Manager.
I needed the spring.main.allow-bean-definition-overriding: true setting.
There may be more to my solution that I should share but I have been at this for a couple of days and have gone in circles. I even remember getting what appeared as a hung process time and and killed the job thinking it was hung. I may have had some "success" early on but just was too quick to kill the execution.
I would still like to know why it is taking so long to create the H2 Entity Manager.
Thanks, Wes.
I am planning to use Spring JdbcTemplate to access my database. Is it a must to use spring-data-jdbc when using JdbcTemplate? The reason I am asking is I don't need "entity"(POJO) for my table in my application. Would it add some overheads if I use spring-data-jdbc?
You can use the JdbcTemplate without Spring Data JDBC without a problem.
JdbcTemplate existed for many years before Spring Data JDBC was conceived.
Spring Data JDBC does involve an overhead.
It extracts data from POJOs, creates queries and transforms the result back to POJOs.
Of course all that takes resources.
If you don't need/benefit from it don't use it.
You can also start with JdbcTemplate and later start using Spring Data JDBC without a problem if the need arises.
JdbcTemplate is part of the spring-jdbc module, so you only need that (and sprint-tx, which includes the DataAccessException hierarchy).
spring-data-jdbc adds support for (not surprisingly) spring-data on top of spring-jdbc. So you don't need it to use JdbcTemplate, the same as you don't need spring-data-jpa to use the JPA EntityManager.
Spring-data-jdbc is implemented on the basis of spring-jdbc. If you don't need Entity at all, then using spring-jdbc to interact directly with the database is the most convenient and flexible. In this case, using spring-data-jdbc is just a pure increase in learning costs. Spring-data-jdbc is designed for DDD (Domain Driven Design) mode, which is different from the current mainstream programming model. The learning cost is not low...
I working on a project which uses Spring boot , Spring Data JPA and postgres .There is a problem that can't solve .
When my application start up ,The database not ready yet . It need to add to application at runtime . But I also want to initialize a database using JPA.
just like spring.jpa.hibernate.ddl-auto：create-drop，Unfortunately Initialize a database using JPA will happen at application startup.
My question is that how to delay spring data jpa DDL generation. now we can't add a datasource at application runtime.
I am searching for a long time on net. But no use. The AbstractRoutingDataSource may be not suit for us, because we don't have a datasource at begin .
Please help or try to give some ideas how to achieve this
Thanks in advance
AbstractRoutingDataSource is not useful as it requires pre-configured datasources.
just check this stackoverflow question, it shows how you can add/remove datasources at runtime. While it doesn't support hibernate's delayed ddl creation but you can create database tables in runtime datasources using schema.sql and inserts some constants using data.sql.
I am using Spring Data Jpa version 1.0.0.M2 here is the url:
http://static.springsource.org/spring-data/data-jpa/docs/1.0.0.M2/reference/pdf/spring-data-jpa-reference.pdf
All is promised to be very simple and nice, but when it comes to two datasources it breaks down. The question is how to setup with two data sources? The JpaRepository automatically searches for EntityManager, when it finds more than two it throws exceptions.
If you have any idea with EntityManager and how to setup the spring data jpa, please post a reply. Your help is truly appreciated!!!
<jpa:repositories base-package="org.springframework.data.jpa.repository.sample"
entity-manager-factory-ref="secondEntityManagerFactory" />
You can use a dynamic datasource that wrap your two datasources, as explained here:
http://blog.springsource.com/2007/01/23/dynamic-datasource-routing/
Are you looking to use 'EntityManager-A' with Spring Data JPA and 'EntityManager-B' for another data access layer?
Mark