Does anyone know of a Java compatible Relational Database Management System, like Microsoft Access, that doesn't require a server side daemon to manage concurrent IO?
Without a server process somewhere, you're talking about a database library like HSQLDB, Derby or SQLite. They work reasonably well as long as you're not expecting lots of concurrent updates to be performant or stuff like that. Those DB servers that are so awkward to set up have a real purpose…
Be aware that if you're using a distributed filesystem to allow multiple users access to the database, you're going to need distributed locking to work (really very painful; too many SO questions to pick a good one to point to) or you're going to have only one process having a connection open at once (very limiting). Again, that's when a DB server makes sense.
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I am a Java guy, I can work with Oracle Database, I know PLSQL, SQL. But I am not good at managing database servers. I think it is a completely different area.
My question is related to database replication. I googled it, found millions of answers but I am still confused.
I could see many times in my professional carrier that developers create complete (complicated) applications to keep sync the source database schema to a target one. It takes time to develop sync apps and very hard to maintain them, especially in case of any data structure modification for example in tables.
I could see that apps built with JPA, JDBC, Spring, myBatis, and PLSQL as well. Usually, they sync DBs during the night, scheduled by Cron, Quartz, Spring, etc. During the sync process usually, the source DB is only available for querying data, not for inserting and DB constraints and triggers are disabled.
These kinds of custom applications always scare me. I do not believe that there is no general, easy, and official way to keep sync two databases without developing a new application.
Now, I got a similar task and honestly, I would like to write zero lines of code related to this task. I believe that there are recommended and existing solutions, cover this topic offered by the database vendors.
That would be great if you can push me in the right direction. I feel that writing another new DB sync application is not the right way.
I need to focus on Oracle Database sync, but I would be happy to know a general, database vendor-independent way.
There are many ways to perform replication in a Oracle Database. Oracle has two replication techniques in the database "Advanced Replication" and "GoldenGate". GoldenGate us the new perferred method of replication which uses the redo logs files from the database. Both methods are geared for a Oracle DBA.
Often application developers will create a "interface" that will move data from one database to other. A interface is a program ( pl/sql, bash, c, etc ) that runs on a cron (database or system) that wakes on a event to move data. Interfaces are useful when data is needed to be process during replication.
It is getting burdensome on my team to prototype tables in MySQL that back our Java business applications, so I'm campaigning to use SQLite to prototype new tables and test them in our applications.
These tables are usually lightweight parameters, holding 12 to 1000 records at most. When the Java applications use them they are likely to be doing so in a read-only capacity, and typically the data is ingested in memory and never read again.
Would I have a problem putting these prototype SQLite tables out on a network, as long as they are accessed via read-only and in small volume? Or should I copy them locally to everyone's machines? I know SQLite does not encourage concurrent access on a network, but I'd be surprised if more than one user would hit it a the same time given the number of users and the way our applications are architected.
If you are using a three-layer architecture, only the application server should have access to the database server. Therefore, you should have control over the connections (i.e. you can create a very small connection pool).
Embedded databases are not suited for lots (hundreds) of concurrent connections. Nevertheless, having into account the amount of data and that you will only focus on read-only queries, I doubt that would be a problem.
A major problem I foresee is that you can have serious problems in terms of SQL dialects. Usually embedded databases use the ANSI SQL standard, but mySQL and others allow you to use their own SQL dialects which are incompatible. It's usually a good practice to have a unit test that runs all the SQL queries against an embedded database to guarantee that they are ANSI-compliant. This way, you have a guarantee that you can use your application (automatically or manually) with the embedded database.
I need to choose between a ad-hoc solution with JSON or pick one embedded NoSQL DB (OrientDB probably).
Scenario:
Open-Source desktop software in Java (free as beer)
Single connection
Continuous Delivery (will change)
Really easy client installation (copy and paste)
about 20,000 records
polyglot persistence
The problem:
setup NoSQL DB is hard
one environment build, interoperability (Linux and Windows)
lack of embedded Document NoSQL DB for Java
complexity
So JSOn ad-hoc is the right option? Some recommendation of a really embedded NoSQL database? or another approach?
Thanks.
One of the main motivations behind the development, and adoption, of NoSQL databases is the possibility to scale horizontally which is needed when your database reach a huge enough size that may require more nodes processing its operation to be more responsive.
If improve performance is the motivation one should have to move a database to a NoSQL approach when it is reaching a huge amount of data. As a side note, it is even interesting to think about the etymology behind the name of one of the most successful NoSQL databases so far, MongoDB that get the prefix "mongo" as a reference to humongous: enormous. This clearly states the purpose of such tools.
That being said, considering that in your scenario you are dealing with 20 thousands records only, you may have many other NoSQL alternatives that are easier to manage. You can go for JSON ad-hoc, or even use more tradicional, solid and stable tools like Firebird embedded or the most obvious and widely used option for embedded databases: SQLite.
I want to make a java application with a rather small database. The pc on which I want to install this has nothing of database stuff on his pc (no wamp server, no oracle, nothing...). I'm rather new in this kind of stuff, and i don't know if it's already been asked but this is what i want to accomplish
Now I have a couple of questions:
Is this doable?
What should I use? Mysql, Oracle,...
How can i do this?
I hope this is enough to get a decent answer.
Yes, it is doable.
For use with Java, I strongly recommend Apache Derby because
you have the huge flexibility of being able to choose between embedded and client-server db, with no code refactoring needed to change data access mode
over H2 or HSQLDB: according to my experience I've found Apache Derby
to be much more reliable/resilient (other embedded DBMSs tend to break more than derby when power fails)
to eat up less RAM
to have better performance on bigger deployments (lots of rows, lots of data [in microbenchmarks with little real-world data H2 and HSQLDB can actually score better]).
to be particularly fast with select queries in heavily multithreaded environments
over MySql and PostgreSql
it's actually faster, when you are not CPU/network -bound, because I've seen it perform better than them in many cases (especially with bigger DBs -- say 10GB) when it comes to filesystem access (MySql and PostgreSql, however, are more efficient in terms of CPU/network utilization, when these are a constraint)
over MySql, PostgreSql, Oracle db, etc.
it's surprisingly fast (often faster), with very big DBs (say, 30 GB) -- something one wouldn't expect from a DBMS you can embed in any application with no deployment/configuration
To get started, see
Apache Derby Getting Started guide
Apache Derby tutorial
Apache Derby FAQs
WorkingWithDerby wiki
If you don't need clients from the network to remotely connect to your database, an "embedded database" is what you want to implement.
Flame-preventing disclaimer: all the statements above are according to my very own personal experience, with the projects I've worked on and/or articles/benchmarks that I read and trusted as reliable. Unless otherwise stated (and in fact I'm not stating otherwise anywhere :) ), I'm referring to fresh out-of-the-box un-fine-tuned installations.
You should probably use an embedded database like H2 or HSQLDB. They are just a simple libraries that you drop in your application, but they provide exactly the same JDBC interface.
You can use the full power of SQL database without any external dependencies. H2, my personal favourite, allows you to create in-memory as well as persistent databases, you can optionally connect to it using socket, it can expose web interface over default 8082 port, so on and so on. On my developer machine I don't even have "normal" database installed, I always use H2.
HSQL or use one of the SQLite JDBC adapters.
I recommend using Derby database. It is very simple to embed in java application.
How is this computer's hardware? What CPU memory and hard-disk?
What is the OS? Do you have the administrator/root access?
If you have a typical PC with windows OS, and enough CPU, memory and hard-disk.
I recommend you to install mysql. Just download the mysql for your OS and install it.
Download link:
http://www.mysql.com/downloads/mysql/
Here is install documents:
http://dev.mysql.com/doc/refman/5.5/en/installing.html
Good luck.
I am developing a web application with php that needs to synchronize a local mysql database that a java desktop version of the web application is interacting with. At the same time i also need the local db to synchronize with the remote db. How do i do this without using other software like MySQL Compare. I will really appreciate the help. Thanx guys.
You clearly have a significant architecture issue. It needs to be planned very well. Two-way replication clearly isn't going to work unless you have thought it out very carefully and understand how to do conflict resolution and what impact that will have on your application. In particular, you can forget using AUTO_INCREMENT.
For one-way replication, you can use mk-table-sync, or use mysql replication in some way (there are a variety of possiblities).
You can also run another mysql instance on the server, use mk-table-sync to periodically synchronise it locally, and use mysql replication on that. This has some benefits, particularly if there are some tables you don't want to replicate.
You really need to think about how it's going to work, if you plan to do two-way synchronisation. It is possible that you may end up writing custom code to do it, as the conflict resolution mechanism may mandate it.