The PL/SQL Wrapper converts PL/SQL source code into an intermediate form of object code. By hiding application internals, the Wrapper prevents. Misuse of your application by other developers. Exposure of your algorithms to business competitors.

Develop Java applications with Oracle Database using JDBC

This quick start guide helps Java developers to successfully establish a connection to the Oracle Database. Follow these easy steps to get started:

Step 1: Prerequisites

• Get access to the Oracle Database instance. You can either create an Oracle Database in the Cloud or Install an Oracle Database
• Install JDK8¹
• Download 18.3 JDBC driver (ojdbc8.jar) and place it at a location accessible to your Java program.

Step 2. Setting up the Connect String

• Download DataSourceSample.java or UCPSample.java from Github

• Modify the Java code and Update the Database Credentials of the database that you have access to.

  

  (a) Change the connect string to use your database's username, password, host name/IP address, database service name, and port number,

  Puxing 6 in 1 serial number. Example: DB_URL = 'jdbc:oracle:thin:@myhost:1521/myorcldbservicename'DB_USER = 'hr' and DB_PASSWORD ='hr'

  (b) Sample code uses the HR.EMPLOYEES table. If you do not have the HR schema in your database, modify the tables and columns in the code to use a table that you do have access to or even use a simple query 'Select sysdate from dual' for testing purposes.

Step 3. Build and Run a Sample Java Program

• Compile the Java code

  javac -classpath ./pb/ojdbc8.jar:. DataSourceSample.java

  javac -classpath ./pb/ojdbc8.jar:./pb/ucp.jar:. UCPSample.java

• Run the sample Java program

  java -classpath ./pb/ojdbc8.jar:. DataSourceSample

  java -classpath ./pb/ojdbc8.jar:./pb/ucp.jar:. UCPSample

• 1 If you have JDK7 or JDK6 then you must use ojdbc7.jar or ojdbc6.jar from 12.1.0.2 or 12.1.0.1. Use 'java -version' to check the JDK version that you have installed. Use 'java -jar -ojdbc8.jar' to check the JDBC driver version.

A wrapper function is a subroutine in a software library or a computer program whose main purpose is to call a second subroutine^[1] or a system call with little or no additional computation. Wrapper functions are used to make writing computer programs easier by abstracting away the details of a subroutine's underlying implementation.

Purpose[edit]

Wrapper functions are a means of delegation and can be used for a number of purposes.

Programming convenience[edit]

Wrapper functions can be used to make writing computer programs easier. An example of this is the MouseAdapter and similar classes in the Java AWT library.^[2]Wrapper functions are useful in the development of applications that use third-party library functions. A wrapper can be written for each of the third party functions and used in the native application. In case the third party functions change or are updated, only the wrappers in the native application need to be modified as opposed to changing all instances of third party functions in the native application.

Adapting class/object interfaces[edit]

Wrapper functions can be used to adapt an existing class or object to have a different interface. This is especially useful when using existing library code.

Code testing[edit]

Wrapper functions can be used to write error checking routines for pre-existing system functions without increasing the length of a code by a large amount by repeating the same error check for each call to the function.^[3] All calls to the original function can be replaced with calls to the wrapper, allowing the programmer to forget about error checking once the wrapper is written.A test driver is a kind of wrapper function that exercises a code module, typically calling it repeatedly, with different settings or parameters, in order to rigorously pursue each possible path. It is not deliverable code, but is not throwaway code either, being typically retained for use in regression testing.An interface adaptor is a kind of wrapper function that simplifies, tailors, or amplifies the interface to a code module, with the intent of making it more intelligible or relevant to the user. It may rename parameters, combine parameters, set defaults for parameters, and the like.

Multiple inheritance[edit]

In a programming language that does not support multiple inheritance of base classes, wrapper functions can be used to simulate it. Below is an example of part of a Java class that 'inherits' from LinkedList and HashSet. See Method for further implementation details.

Library functions and system calls[edit]

Many library functions, such as those in the C Standard Library, act as interfaces for abstraction of system calls. The fork and execve functions in glibc are examples of this. They call the lower-levelfork and execve system calls, respectively.

This may lead to incorrectly using the terms 'system call' and 'syscall' to refer to higher-level library calls rather than the similarly named system calls, which they wrap^[4].^[5]

See also[edit]

• Language binding wrapper to another language
• SWIG automatic wrapper generator

References[edit]

1. ^Reselman, Bob; Peasley, Richard; Pruchniak, Wayne (1998). Using Visual Basic 6. Que. p. 446. ISBN9780789716330.
2. ^The Java Tutorials
3. ^Stevens, Richard; Fenner, Bill; Rudoff; Andrew M. (2003). UNIX Network Programming. Addison-Wesley. pp. 5–6, 29. ISBN9780131411555.
4. ^'syscalls(2) - Linux manual page'. man7.org. Retrieved 2020-04-25.
5. ^'System Calls (The GNU C Library)'. www.gnu.org. Retrieved 2020-04-25.