For school project I had to make program in Java that uses data base and to do so I had to import to that project file ojdbc6.jar. I know that without it I couldn't use data bases but I don't really know what is this file. Could someone explain? How such file is called and what exactly is its purpose?
Simply stated, a JDBC driver is a suite of classes that map the functionality required by the JDBC API onto the functionality provided by a specific kind of database.
Each database uses a different "wire protocol" to communicate between code running in a database client and the database server. JDBC "abstracts that away" so that a Java program can talk to any vendor's database (more or less1). The JDBC driver is the "glue" that makes the abstraction work.
In the Oracle case, there are multiple JDBC drivers, for various purposes including
Thin drivers versus OCI or server-native drivers (OCI & server-native drivers depend on platform specific native libraries)
Client-side versus server-side drivers (server-side libraries are optimized for cases where the client code is running on the database server machine ... for example.)
Drivers for different versions of Java; e.g. supporting different JDBC conformance levels.
The "ojdbc6.jar" file constitutes the Oracle thin client-side JDBC driver which is compatible with Java 6 (JDBC level 4.0).
For more information, read the Oracle JDBC FAQ.
1 - There are a couple of issues that make cross-database compatibility difficulty. Firstly, different databases support different dialects of SQL and provide different sets of SQL data types. Secondly, certain database vendors (including Oracle, before they bought Sun) have implemented non-standard extensions to JDBC.
Related
The question is pretty self-explanatory, but below is some more info about the situation:
I am building a Java program that will be replacing a program that consists of an Excel user interface with an Access database. The Excel program connects to the Access database and communicates with VBA. But, so far there has only ever been one user at a time. Now that the program is due to expand, we need many users to be able to write to any table at the same time.
Access allows multiple users to connect at once, of course. This is not possible in HSQLDB, which is what prompted the question. Obviously, this is better accomplished with a server, but the plan is to build the program using the current database and then accomplish the transition to a server later.
Thanks in advance
In order to support multiple concurrent users (processes) writing to an Access database you must use the Access Database Engine. The options to do that from a Java application are:
Use Java's own JDBC-ODBC Bridge and the Access ODBC driver. (Note that the JDBC-ODBC Bridge was removed from Java 8.)
Use a third-party JDBC-ODBC Bridge and the Access ODBC driver.
Use a third-party JDBC driver that works with the Access Database Engine (if such a thing exists).
Note especially that the UCanAccess JDBC driver does not use the Access Database Engine and therefore does not support multiple concurrent users (processes) writing to the Access database.
You can do it. I have a similar application that I use. In version 1.8 of Java, the ODBC bridge was removed, so you'll have to look into using a separate library to connect, assuming you are using 1.8 or above. For me, it's way slower, but it does work. check out
Removal of JDBC ODBC bridge in java 8
I use "Ucanaccess" for my program, which is one of the suggestions in that question.
I am Using Oracle Database 10g Express Edition with Java.
Link:
http://srikanthtechnologies.com/articles/oracle/java.html
3 types of connections with different drivers are depicted
i want to know that can all these 3 connection be made in any situation or these are used in specific cases ?
The 2/3 are almost the same. Both of them uses jdbc:oracle:thin driver. The only difference is the invoker (DriverManager vs. OracleDataSource).
The 1st uses oci driver (jdbc:oracle:oci8). This is totally different with thin driver. Thin driver is 100% implemented in Java. So no more library is needed. But OCI driver needs Oracle OCI client, which is implemented in C/C++ (You must install it before you use the oci driver). As a result, it is platform dependent (C/C++ library).
Some people thinks the performance of OCI is better than thin, because OCI is implemented in native C/C++. But Oracle never releases an official document to prove that.
Now most apps use thin driver, because it is easy to deploy (Do not need the Oracle OCI client). And to be decoupled with the Oracle classes (OracleDatasource), most people use DriverManager to load the oracle thin driver, or a Connection Pool.
I am considering using a Microsoft access database for a Java project. My question is, if I use a Microsoft access database and I complete my project and run it as a jar file on any computer/operating system, does any computer/ operating system need to have Microsoft access installed on it, particularly if the database needs to be put on a GUI on the java program and the administrator of the program can add and remove entries.
You will have to install the access odbc driver on any machine that accesses the database. I think you can do this by installing the Access runtime stuff without installing all of Access. Keep in mind that this sort of data-access is file-level, so your performance will be very poor. I'd suggest that you use a real database (postgres, mysql, sql server, oracle) or maybe a lightweight one such as SQL Server express and then accessing that database using either an odbc-jdbc bridge or preferably a native jdbc driver. Using a native jdbc driver will let you run your app from a non-windows environment.
You can use a Access Database via the JDBC-ODBC bridge on every Microsoft Windows system without to install Microsoft Access. You only need the Access Database Engine (ACE) formerly known as Jet Database Engine. ACE is part of current Windows versions. For older ones it may be necessary to install the Microsoft Data Access Components (MDAC).
Using a Access Database from Java has some disadvantages:
This is a type 1 driver with native code. Generally pure Java JDBC drivers are more performant.
With JDK 6 the JDBC-OLE bridge was somewhat enhanced. But there are still some problems with charsets and CLOBs.
Your application is restricted to Microsoft Windows operating systems.
According to the JDK 7 JDBC-ODBC bridge guide the JDBC-ODBC bridge will be removed in JDK 8:
The JDBC-ODBC Bridge should be considered a transitional solution; it will be removed in JDK 8. In addition, Oracle does not support the JDBC-ODBC Bridge. Oracle recommends that you use JDBC drivers provided by the vendor of your database instead of the JDBC-ODBC Bridge.
So if there is any chance to use another database for your project, you should avoid using Microsoft Access together with Java.
There are lots of alternatives with far more better JDBC drivers.
If you want a small footprint embedded database, there are:
Java DB (part of the JDK), also known as Apache Derby
H2
HSQLDB
SQLite e.g. with Xerial driver
(Java DB, H2 and HSQLDB are pure Java solutions)
If you prefer a client server solution, for most commercial and open source there exist full-fledged JDBC drivers.
Oracle
Microsoft SQL Server (the server has to run on Windows but your Java client can run on every OS that supports a JVM. See Microsoft JDBC Driver for SQL Server Support Matrix)
PostgreSQL
MySQL
I'm trying to select a JDBC driver for an application I'm building and I've found lots of drivers, but I can't seem to narrow the selection down to one. The driver I select should have the following features:
Free for commercial use
Easy to install (eg. single jar file, no drivers to install)
Easy to use (well documented)
No database server required
Multi-user / Network support
What JDBC database drivers would you suggest?
So far I've considered TinySQL and SQLite.
The database is not very large think maybe 10k records.
The JDBC driver depends on the database you want to use. Some free databases include:
Derby (small, lightweight, comes with Java 1.6)
MySQL (bigger, lots of features)
PostgreSQL (bigger, lots of features)
I'm sure there are others.
When you install the database, the documentation will tell you where to get the JDBC driver.
Unless you have specific requirements, I would have suggested that you use MySQL, it is free and very popular. Also, it is very easy to use through JDBC. However, I then saw your comment:
I want to use a JDBC driver so if I
change databases the database will
have the same interface. Right now I
need a database that meets the above
requirements.
The problem is that, as far as I know, JDBC alone isn't that flexible. With JDBC you basically pass strings to and fro the application and the database engine. If you want something that allows you to change the database but doesn't impact the way that your application and database communicate, you should consider and ORM tool like Hibernate.
The OP asked for 'no database server'. That means that there are two options in common use: Derby and HSQLDB that integrate well into Java.
I am doing an undergrad final project, and need to justify my choice of MySQL for the database element of my project. Truth is, it's the only one I can really use, and hence I went for it.
What other database systems could I have used? Any advantages and disadvantages of these over MySQL?
In fact, you can use every database which is accessible through a JDBC driver. Almost all self-respected RDBMS vendors provides a fullworthy JDBC driver for download at their homepage. Just Google "[vendorname] jdbc driver download" to find it. Here's an overview:
MySQL JDBC driver
PostgreSQL JDBC driver (note: older versions doesn't support generated keys).
Oracle JDBC driver (note: older versions doesn't support generated keys).
MSSQL JDBC driver (or performancewise better, the jTDS JDBC driver)
DB2 JDBC driver is hard to find in IBM's online forest, but it's usually already included in the /java folder of the DB2 installation.
This way you can use the JDBC API transparently to access either of the databases.
As to which database to choose, just look at the features, robustness, performance, etc the RDBMS provides and the budget you have -if it isn't freeware. I myself tend to prefer PostgreSQL.
Instead of a fullfledged database server, you can also consider an embedded Javabased database, such as Sun Oracle JavaDB, Apache Derby, HSQLDB or SQLite, each which are of course accessible through the JDBC API the usual way.
You can use any relational database that has a JDBC driver. These would include PostgreSQL, Hypersonic SQL, MySQL, SQLLite on the free side and Oracle, MS SQL Server, and others on the paid side.
The biggest advantage accrued to MySQL in your case is that it's free and you know it. That's enough to make it suitable for what you want to accomplish.
You could have used pretty much ANY database. MSSQL, SQLite, Postgre, Oracle or [put your choice here]
There's a driver for pretty much any database to integrate with Java. This is a great place to find out all the DB's java support, as well as how to integrate
Hope this helps
Have a look at the list of vendors who have endorsed the JDBC API maintained by Sun. Also see the list of third-party JDBC technology-enabled drivers which are currently shipping.
You mentioned MySQL and database. For the case you are free to usa a non RDBMS you can check db4o.
Advantage: pure OO/Java persistence.
Many have said this already, but pretty much any database will work. Consider including the top 5 (based on rankings, popularity) in your writeup.