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Forum
10

Master database switching to read-only mode, possibly caused by slave failure

We had a database failure causing a production outage. Both master and slave databases have failed ... database failed first and possibly caused the master to switch to read-only mode. The sequence ... - MASTER instance stopped responding to write requests. All requests sent to the database during 3
Forum
10

Multi-Threading/Distributed-Database Questions...

Greetings ObjectDB team, All below questions assume a very large database (~1,000,000,000 objects ... : Is it true that two read-only JPQL queries accessing the same database file actually run simultaneously ... to use two database files on two different physical hard disks while still being able to cross reference
FAQ
10

What is the Java Persistence API (JPA)?

The Java Persistence API (JPA) is a standard API for accessing databases from within Java applications. The main advantage of JPA over JDBC (the older Java API for interacting with databases ... . Using plain old Java objects (POJO) to represent persistent data can significantly simplify database
Manual
10

Deleting JPA Entity Objects

Existing entity objects can be deleted from the database either explicitly by invoking the remove ... from the database it has to first be retrieved (no matter which way) and then in an active ... (); The entity object is physically deleted from the database when the transaction is committed. Embedded
FAQ
10

Which API should I use - JPA or JDO?

code. When to prefer JDO JDO might be preferred when portability to other object databases is more important than general portability to both object and relational databases. JPA is designated to be used mainly with relational databases. ObjectDB is the only object database that supports JPA
Tutorial
10

Step 4: Add a Servlet Class

{ // Obtain a database connection: EntityManagerFactory emf = (EntityManagerFactory ... ") .forward(request, response); } finally { // Close the database ... , and then an EntityManager (representing a database connection) is constructed. If a new guest
FAQ
10

Is ObjectDB scalable? What are its limitation?

ObjectDB is highly scalable and can manage efficiently databases in a wide range of sizes, from ... supports: Database file size up to 128 TB (= 131,072 GB = 134,217,728 MB). Up to 2,147,483,648 entity classes per database file. Up to 2,147,483,648 indexes per database file
Tutorial
10

Step 4: Add a Servlet Class

ServletException, IOException { // Obtain a database connection: EntityManagerFactory ... { // Close the database connection: if (em.getTransaction().isActive ... is retrieved from the application scope attribute, and then an EntityManager (representing a database
Forum
10

Convert embedded database to server

Hello, What is the right way to convert an embedded database to a server one ? As a result ... data directory, start the server, and access the database from your application using a client ... database ( with remote connection enabled ) and a real server instance database ? Regards
Issue
10

Database File Compression

ObjectDB database files are usually smaller than database files of other Database Management Systems (object databases and relational databases) but additional internal compression is still possible ... . So the effect of using compressed ObjectDB database file on performance is unknown yet.