I couldn't find an answer to this question. How can I export a Java project that makes use of a PostgreSQL database?
I want to use the same database on another computer. Do I need to export the database itself with the project? How can this be done?
What should the connection URL be, so that the database is accessible on another computer?
I'm using JDBC, and I'm on Windows.
Thanks in advance.
EDIT: Wouldn't I also need to dynamically retrieve the username and password on the other computer, instead of using the specific username and password I have on my computer in PostgreSQL?
It really depends on what you want to achieve.
Shared database between hosts
Do you want the application on both computers to use the same database, so that changes made by one are seen on the other? If so, you need to configure each copy of the application to connect to the same database instance on one of the machines. This is usually done by changing the JDBC URL. You'll need to configure PostgreSQL on the machine that'll be the database server so it allows connections from the other hosts, ensure they can talk to each other over TCP/IP, etc.
Fresh DB on each host
Do you want each install to have a separate instance of the database, so changes made on one have no effect on the other, and where each instance starts out with a blank, empty database (or one with only static contents like lookup tables)? If so, you should generally define the database using SQL scripts, then have the application run the SQL scripts when first installed on a machine. If you've defined the database by hand so far, you can use pg_dump to create a SQL script that you can use as the basis for this, but I really advise you to look into tools like Liquibase for schema management instead.
"Fork" current state
Do you want each instance of the application on a machine to have an independent database, so changes made on one have no effect on other instances on other machines, but where the starting state of an install is what was in the database on the other host? If so, you need to dump and reload the database alongside the application, using pg_dump -Fc and pg_restore. You can automate this within your application / build system using tools like ProcessBuilder, or do it manually.
There's no generic, canned way to do this. It'll require you to define an application deployment procedure, maybe produce an installer, etc.
Related
I wanted to create an executable of my java application in eclipse, but instead of having to hosting my database, I wanted to putting inside the application's folders when creating the executable, what do I need to do to accomplish this, and also, what would the path of the class with the code to connect to the database be like?
Thanks in advance.
You cannot do this with MySQL, since MySQL runs in "server mode" only.
To do what you want you would need to change the database to one of the following:
H2. See documentation. URL: jdbc:h2:file:<path>/<database>
HyperSQL. See documentation. URL: jdbc:hsqldb:file:<path>/<database>
Apache Derby. See documentation. URL: jdbc:derby:<path>/<database>
In all three databases the corresponding JDBC driver includes the WHOLE database engine itself. Therefore, just by connecting to the database, you'll get a fully running instance of it.
Now, these databases can work on several modes:
Embedded+File System: the JDBC URL will include a [relative or absolute] path to a directory where the database tables and data are persisted.
Embedded+Memory: the JDBC URL will specify all data will be stored in memory and will be lost once the connection is closed.
Server Mode: the JDBC URL will point to an [external/remote] host:port where the database engine is running. This is similar to MySQL.
According to your question, the first option seems to be the one you need. As a personal note, I find H2 and HyperSQL are easier to set up compared to Derby, since each one comes into a single JAR file.
A database is either located on a user's local machine (for development), or on a server on the internet (for real world use). You could create a Java class that imitates a database, but it's impossible to put a database inside an executable.
If I have a setup where I need to run some SQL across several different database environments from a single Java program, is there a way to configure a connection pool to achieve this?
When I say several different database environments, what I mean is that I have several different versions of the same environment (staging, development, unit test, pre-prod etc). I want to create something that can run the same SQL query across each environment against the script logging table to ensure that each environment has had the same scripts run against them. We've had issues where the environments have got out of sync and bad things happened. While we are improving the process to try and reduce this, a tool is also required so we can check that what has been actually run.
Currently we have a pool property that passes in the URL that points to each environments connection.properties files. This is fine for the current connection pooling, but not sure if this will work for multiple databases.
If you need to connect to many different databases at the same time then you should use a different connection pool for each database. It just doesn't make any sense to use the same pool for different databases as a connection to one database will never be able to be re-used for another database.
If you need to connect to a different database depending on external configuration (such as command-line, properties file) then you should arrange for the differing connection strings to be used depending on the environment setting.
What is your application server? Best solution is to "hardcode" some symbolic connection pool name into the application. Then you can use the same signed version of .jar/.war/.ear file in every environment.
To name the real database you can either use JNDI mapping on application server level. Or you can also use tnsnames.ora/sqlnet.ora(default domain) mapping as this is usual way how to manage this in Oracle world.
I read a lot of posts like:
querying embedded database in netbeans using derby
But still I'm having trouble to understand embedded databases.
1) I create a Derby database on Netbeans and I can create tables, link the database to a form and submit the data and update the records with no problem.
2) The problem arises when I want to make the program portable. I apply Clean and Build, then copy the dist folder and also copy the libraries, database, etc ... but when running the program does not recognize the database
3) I read in several places that it is appropriate that the database is created by code using something like
String host = "jdbc: derby: // localhost: 1527 / EmployeesCreateTrue; create = true"
and not creating the database on Netbeans Service...
If I do this procedure with code the database is created but it does not appear or does not allow me to connect from NetBeans and I wish I could fix it to create tables from NetBeans and not from code.
4) I read manuals "how to import a database from Derby to NetBeans" and it doesn't work...
Question: What is the best way to create a database, tables and connect to NetBeans for the final application to be easily portable?
1) Create the database on Netbeans with the wizzard?
or
2) Just plain code on the application?
I don't understand precisely what you mean by "the database is created but it does not appear."
I think if you were to explain that precisely, the community could probably help you.
There are three common reasons for "table does not exist" when you think you've created the tables; I've explained those cases in this answer: Is it necessary to create tables each time you connect the derby database?
Please let us know more information about your situation so that we can help you better understand the behavior of your application.
I'm not 100% sure if this is your problem, but a lot of problems people seem to have with Netbeans and Derby seems to come from the fact that they don't set derby.system.home explicitly. When you don't, Derby stores databases in the current directory, and that is likely different when working in the IDE, either in the Services tab, or your own code, than when you execute your app's jar as a standalone program. So the advice (which you will also find in the manual) is: always set derby.system.home. An alternative would be to use full paths to the databases, but that rarely works well for a real application that is deployed on different machines.
I had the same problem --had the derby db in the services but the netbeans coded programs didn't access it. I solved it by adding the derby database (copy paste) to the package in the Files section. I use Windows 7. Once I did that, I was able use multiple tables (before netbeans just ignored secondary tables and only allowed me to use the primary table).
I created a java swing application using a MySQL database.
So I want to create an installer for the application so as it could be installed and runned on every pc having JRE installed.
After some researches, I found a way to achieve this using Launch4j and Inno Setup Compiler after generating the jar file.
The problem is that I don't know how to integrate the mysql database so as the application can be seen as a whole.
Thanks in advance
It is more a comment that anything, but I need the extra space/formatting:
A MySQL install is not something I would do automatically for a user because:
a) You are creating services that the user may not know how to manage. You are installing a program that will open ports, that may need security updates, etc. If your final user has no IT background to properly manage that, it is clearly a security issue.
b) Maybe the user prefers another configuration. OTOH, if the user knows what he is doing, maybe he already has a MySQL install. He may prefer just to run your DB inside the MySQL that is already installed, because it is properly configured (including backups), it is in redundant hardware, whatever.
If you need a small, embedded database with your product, switch to Derby or Hypersonic.
If your product requires a full MySQL install, just provide (and document) a way for an IT operator do the installation by itself (give the SQL scripts to create and populate the database together with the code, specify how to configure the DB parameters in your application).
i have a java project with mysql database
i am using advance installer to create a setup file...
i can embed jre to run the software(Without installing java in the system).
like wise,i want to embed the mysql database (system doesn't contains mysql )...
.There is any software to embed mysql database in my project setup...
MySQL is very difficult to embed correctly and there are a number of failure states that might occur if it is not shut down using the proper procedure. SQLite is a much better engine for this sort of thing and is used by a number of applications as a persistent backing store. While not as powerful as MySQL, it is much more resilient. It also has the advantage of not requiring a separate process.
SQLite's storage method is to persist things into a file that can be copied, moved, or backed-up without any issues. MySQL involves many such files, some of which are in an inconsistent state unless the correct FLUSH is called.
The best you can do with MySQL is bundle it, not embed it, but then you'll be responsible for setting it up on the host system, configuring it correctly, running the appropriate maintenance procedures, and providing some kind of back-up facility for the database itself.