To create an indexed file you need a Key. To create a Sorted file, you need to order the records. The typical differences between these two files are Order and Key.
How to write Query to Join Tables
Simple ideas and quickly what you need to find to write a query for joining of two tables explained.
SQL View Remains After Modifying Table
In this post, I have answered one tricky SQL-view interview question. Views availability after the base table modified confuses many developers. I provided an answer to this.
ISO 8583 Bitmap: How to Decode Message
How to calculate or decode which ISO Bits are present or not present in ISO 8583 message. I have explained in easy to understand method.
Indexed file Vs Sorted file
Indexed file
- Indexed files use a primary key field to identify the records of an original file in a database. A primary key field is a unique field. An indexed file consists of actual records sorted based on the primary key field value
- An indexed file also consists of alternate keys, which build the alternate index. Unlike primary keys, the alternate keys in an indexed file do not have actual records.
- The advantage of primary key field values is that because of the indexing of actual records, you require only one input-output operation to access records in an indexed file
Sorted file
- Sorting is like placing records either in ascending or descending order based on KEY
- For example, sorting payroll-file with an employee identification number in ascending order is called Soring. Here, employee identification is KEY.
- Sorting is possible to do on multiple keys like ID and Department
- When you sort a sequential file, its records are stored on the hard disk and you can only access them serially. It is not possible to access all the records of a file simultaneously.
Also Read
