Step-by-Step Guide to Creating Physical Files on an AS400 System

How to Create Physical File in AS400

Creating a physical file in AS400 is an essential task for any programmer or system administrator working with IBM iSeries. Physical files are the fundamental building blocks of database applications on AS400, providing a structured way to store and manage data. In this article, we will guide you through the process of creating a physical file in AS400, covering the necessary steps and considerations to ensure a successful creation.

Understanding Physical Files in AS400

Before diving into the creation process, it is crucial to have a clear understanding of what a physical file is in the context of AS400. A physical file is a collection of records, each with a unique key, and contains fields that define the data structure. Physical files are used to store and retrieve data efficiently, and they can be accessed using various programming languages, such as RPG, COBOL, and CL.

Preparation for Creating a Physical File

Before creating a physical file in AS400, you need to ensure that you have the necessary permissions and access rights. Log in to your AS400 system as a user with sufficient privileges to create a new physical file. Additionally, it is recommended to have a clear idea of the file’s purpose, data structure, and the fields you want to include.

Creating a Physical File in AS400

To create a physical file in AS400, follow these steps:

1. Open the AS400 command-line interface (CLI) or a supported programming environment, such as RDi (Rational Developer for i).

2. Use the CRTFILE command to create a new physical file. The basic syntax of the CRTFILE command is as follows:

“`
CRTFILE FILE(FileName) RCDLEN(RcdLength) RCDTYPE(Fixed/Varying)
“`

– `FileName`: The name of the new physical file.
– `RcdLength`: The length of each record in the file.
– `RcdType`: The type of records in the file (Fixed or Varying).

3. Specify the file’s data structure by defining the fields using the ADDFLD command. The basic syntax of the ADDFLD command is as follows:

“`
ADDFLD FILE(FileName) FLDNAME(Field1) TYPE(FieldType) LEN(Length) DEC(DecimalPlaces)
“`

– `FileName`: The name of the physical file.
– `FLDNAME`: The name of the field.
– `FieldType`: The data type of the field (e.g., CHAR, NUM, DATE).
– `LEN`: The length of the field.
– `DEC`: The number of decimal places for numeric fields.

4. Repeat the ADDFLD command for each field you want to include in the physical file.

5. Save the changes and exit the programming environment or CLI.

Verifying the Physical File Creation

After creating the physical file, it is essential to verify that the file has been created successfully. You can do this by using the DSPFILE command to display the file’s details. The basic syntax of the DSPFILE command is as follows:

“`
DSPFILE FILE(FileName)
“`

This command will show you the file’s name, record length, record type, and field definitions, confirming that the file has been created correctly.

Conclusion

Creating a physical file in AS400 is a fundamental task for anyone working with IBM iSeries. By following the steps outlined in this article, you can successfully create a physical file in AS400, ensuring efficient data storage and retrieval for your database applications.