Inbound Interface

Oracle provides flexible tools in the form of Interface programs to import the master and transactional data like Customers, Invoices, and Sales Orders etc. from external systems into Oracle Applications or to transfer the data from one module to another module.

There are 2 types of interfaces:

Inbound Interface: will be used to upload the data from legacy system (Flat files) into Oracle Applications base tables.
Outbound Interface: will be used to extract the data from oracle Database tables into the flat files.

Conversion/Interface Strategy:

Data Mapping

During the data mapping process, list of all the data sets and data elements that will need to be moved into the Oracle tables as part of conversion are identified. Data mapping tables are prepared as part of this activity that show what are the data elements that are needed by the target system to meet the business requirements and from where they will be extracted in the old system.
Download Programs

After the conversion data mapping is complete, download programs are developed that are used to extract the identified conversion data elements from the current systems in the form of an ASCII flat file. The structure of the flat file must match the structure of the Oracle standard interface tables. These flat files generated may be in text form or a comma or space delimited, variable or fixed format data file.
Upload Program

Once the data has been extracted to a flat file, it is then moved to the target file system and the data from the file is loaded into user defined staging tables in the target database using SQL Loader or UTL_FILE utilities. Then programs are written and run which validate the data in the staging tables and insert the same into the Oracle provided standard Interface tables.
Interface Program

Once the interface tables are populated, the respective interface program (each data element interface has a specific interface program to run) is submitted. The interface programs validate the data, derive and assign the default values and ultimately populate the production base tables.

A typical path to transfer the data from Legacy System to Oracle Apps:

Some Interface/conversion methods and details

UTL_FILE

In the dynamic world of Oracle Applications, the UTL_FILE package is a powerful tool that facilitates interaction between the database and the file system. Whether you’re exporting data, importing data, or performing file manipulations, UTL_FILE is your go-to package. Let’s explore its features, setup, and practical examples to harness its full potential.

What is UTL_FILE?

UTL_FILE is a PL/SQL package that allows Oracle programs to read from and write to operating system text files. It acts as a bridge, enabling seamless data exchange between the structured environment of the database and the file system.

Key Features of UTL_FILE

File Operations: UTL_FILE supports various file operations such as opening, reading, writing, and closing files.
Error Handling: It provides robust error handling mechanisms to manage exceptions during file operations.
Security: Access to files and directories is controlled through directory objects and database parameters, ensuring secure file handling.

Setting Up UTL_FILE

Before using UTL_FILE, you need to set up directory objects in Oracle. Here’s how you can do it:

CREATE OR REPLACE DIRECTORY my_directory AS '/path/to/directory';
GRANT READ, WRITE ON DIRECTORY my_directory TO my_user;

Basic Operations with UTL_FILE

Writing to a File

Let’s start with a simple example of writing to a file:

DECLARE
    file_handle UTL_FILE.FILE_TYPE;
BEGIN
    file_handle := UTL_FILE.FOPEN('MY_DIRECTORY', 'example.txt', 'w');
    UTL_FILE.PUT_LINE(file_handle, 'Hello, World!');
    UTL_FILE.FCLOSE(file_handle);
EXCEPTION
    WHEN OTHERS THEN
        DBMS_OUTPUT.PUT_LINE('Error: ' || SQLERRM);
END;

In this example, we open a file named example.txt in write mode, write a line of text, and then close the file.

Reading from a File

Now, let’s read from a file:

DECLARE
    file_handle UTL_FILE.FILE_TYPE;
    line VARCHAR2(100);
BEGIN
    file_handle := UTL_FILE.FOPEN('MY_DIRECTORY', 'example.txt', 'r');
    UTL_FILE.GET_LINE(file_handle, line);
    DBMS_OUTPUT.PUT_LINE(line);
    UTL_FILE.FCLOSE(file_handle);
EXCEPTION
    WHEN OTHERS THEN
        DBMS_OUTPUT.PUT_LINE('Error: ' || SQLERRM);
END;

Here, we open the file in read mode, read a line of text, and display it using DBMS_OUTPUT.PUT_LINE.

Advance Usage

Appending to a File

To append data to an existing file, use the ‘a’ mode:

DECLARE
    file_handle UTL_FILE.FILE_TYPE;
BEGIN
    file_handle := UTL_FILE.FOPEN('MY_DIRECTORY', 'example.txt', 'a');
    UTL_FILE.PUT_LINE(file_handle, 'Appending this line.');
    UTL_FILE.FCLOSE(file_handle);
EXCEPTION
    WHEN OTHERS THEN
        DBMS_OUTPUT.PUT_LINE('Error: ' || SQLERRM);
END;

Handling Large Files

For large files, it’s essential to handle them efficiently. Here’s an example of reading a file line by line:

DECLARE
    file_handle UTL_FILE.FILE_TYPE;
    line VARCHAR2(32767);
BEGIN
    file_handle := UTL_FILE.FOPEN('MY_DIRECTORY', 'large_file.txt', 'r');
    LOOP
        BEGIN
            UTL_FILE.GET_LINE(file_handle, line);
            DBMS_OUTPUT.PUT_LINE(line);
        EXCEPTION
            WHEN NO_DATA_FOUND THEN
                EXIT;
        END;
    END LOOP;
    UTL_FILE.FCLOSE(file_handle);
EXCEPTION
    WHEN OTHERS THEN
        DBMS_OUTPUT.PUT_LINE('Error: ' || SQLERRM);
END;

Error Handling

UTL_FILE provides several exceptions to handle errors effectively:

INVALID_PATH: Raised when the specified path is invalid.
INVALID_MODE: Raised when the mode parameter in FOPEN is invalid.
INVALID_OPERATION: Raised when an invalid operation is attempted.
READ_ERROR: Raised when a read operation fails.
WRITE_ERROR: Raised when a write operation fails.

The UTL_FILE package is a versatile tool in Oracle Apps, enabling efficient file handling for various applications.