What is File Organization in DBMS? Types and Application?

Abhishek Pratap Singh
6 min readJan 3, 2023

In a database management system (DBMS), file organization refers to the way in which data is stored and retrieved within a database file. There are several different file organization techniques that can be used in a DBMS, including:

Heap file organization-

  • In a database management system (DBMS), heap file organization is a method of storing and retrieving data within a database file in which records are stored in no particular order. This means that new records can be added to the end of the file, and existing records can be deleted from anywhere in the file.
  • One advantage of heap file organization is that it is very fast for insertion and deletion operations. This is because the DBMS does not have to do any sorting or rearranging of the records in the file. However, retrieval can be slower in heap file organization, because the DBMS must search through the entire file to find a specific record.
  • Heap file organization is often used when the records in the file are not accessed frequently, or when the records are accessed in random order. It is also used when the records in the file are frequently inserted or deleted because these operations are relatively fast in heap file organization.
  • One disadvantage of heap file organization is that it can lead to fragmentation, which occurs when there are many empty spaces within the file. This can make the file larger and slower to access, as the DBMS must skip over the empty spaces when searching for records. To prevent fragmentation, the DBMS may need to periodically reorganize the file.

Sorted file organization-

  • In a database management system (DBMS), sorted file organization is a method of storing and retrieving data within a database file in which records are stored in sorted order based on a specific field or set of fields. This makes retrieval fast because the DBMS can use a binary search algorithm to locate a specific record quickly.
  • However, insertion and deletion can be slower in sorted file organization, because the DBMS must insert the new record in the correct position and shift other records as necessary to maintain the sorted order. Deletion can also be slower because the DBMS must shift the remaining records to fill the gap left by the deleted record.
  • Sorted file organization is often used when the records in the file are accessed frequently and in a specific order, such as when running queries that sort the results by a specific field. It can also be used when the records in the file are relatively static, meaning that they are not frequently inserted or deleted.
  • One disadvantage of sorted file organization is that it can lead to overflow, which occurs when there is not enough space in the file to accommodate new records. To prevent overflow, the DBMS may need to periodically reorganize the file by creating a new, larger file and transferring the records to it.

Hash file organization-

  • In a database management system (DBMS), hash file organization is a method of storing and retrieving data within a database file in which records are stored using a hash function that maps the record’s key value to a specific location in the file. This makes retrieval very fast because the DBMS can use the hash function to locate the record directly, without having to search through the entire file.
  • However, insertion and deletion can be slower in hash file organization, because the DBMS must insert the new record in the correct location and shift other records as necessary to maintain the hash function. Deletion can also be slower because the DBMS must shift the remaining records to fill the gap left by the deleted record.
  • Hash file organization is often used when the records in the file are accessed frequently and the access pattern is random, meaning that the records are not accessed in a specific order. It is also used when the key values for the records are unique because the hash function is more effective when there are no duplicate key values.
  • One disadvantage of hash file organization is that it can lead to collisions, which occur when two or more records have the same hash value and are therefore mapped to the same location in the file. To prevent collisions, the DBMS may need to use a more complex hash function or implement collision-handling techniques such as chaining or open addressing.

Indexed file organization-

  • In a database management system (DBMS), indexed file organization is a method of storing and retrieving data within a database file in which an index is created for the file that allows records to be retrieved quickly based on the indexed field or fields. The index is a separate data structure that contains a mapping of the indexed field values to the location of the corresponding records in the file.
  • Retrieval is fast in indexed file organization because the DBMS can use the index to locate the desired record directly, without having to search through the entire file. However, insertion and deletion can be slower, because the DBMS must update the index to reflect the new or deleted record.
  • Indexed file organization is often used when the records in the file are accessed frequently and the access pattern is specific, meaning that the records are accessed based on the values of a specific field or field. It is also used when the records in the file are relatively static, meaning that they are not frequently inserted or deleted.
  • One disadvantage of indexed file organization is that it requires additional storage space to store the index, which can increase the overall size of the database. Additionally, maintaining the index can be time-consuming, as the DBMS must update it whenever a record is inserted, deleted, or modified.

Clustered file organization-

  • In a database management system (DBMS), clustered file organization is a method of storing and retrieving data within a database file in which records are stored based on their physical proximity to one another. This means that records that are related to each other, or that are often accessed together, are stored close to each other in the file.
  • Clustered file organization can improve the performance of queries that access multiple related records, because the DBMS can read the records from the file in a single sweep, rather than having to access them individually. However, insertion and deletion can be slower in clustered file organization, because the DBMS must rearrange the records to maintain their physical proximity.
  • Clustered file organization is often used when the records in the file are accessed frequently and the access pattern is specific, meaning that the records are accessed based on the values of a specific field or fields. It is also used when the records in the file are relatively static, meaning that they are not frequently inserted or deleted.
  • One disadvantage of clustered file organization is that it can lead to fragmentation, which occurs when there are many empty spaces within the file. This can make the file larger and slower to access, as the DBMS must skip over the empty spaces when searching for records. To prevent fragmentation, the DBMS may need to periodically reorganize the file.

Why File Organization?

  • File organization in a database management system (DBMS) is important because it determines how data is stored and retrieved within a database file. Different file organization techniques can be more or less efficient depending on the specific needs of the database and the access patterns of the users.
  • For example, if the records in the file are accessed frequently and in a specific order, sorted file organization may be the most efficient choice, because it allows the DBMS to use a binary search algorithm to locate records quickly. On the other hand, if the records in the file are accessed randomly and the access pattern is not specific, hash file organization may be more efficient, because it allows the DBMS to locate records directly using a hash function.
  • By choosing the appropriate file organization technique, a DBMS can optimize the performance of the database, improving the speed and efficiency of queries and other operations. This can help to ensure that the database is able to handle the needs of the users and support the applications that depend on it.
  • Improved performance.
  • Flexibility.
  • Data integrity.
  • Data security.
  • Space efficiency.

Follow Abhishek Pratap Singh for more, Have a great day!

--

--

Abhishek Pratap Singh

Software Engineer || Co- Founder || B-Plan contest finalist at IIT Kharagpur || 1st Rank on SQL- HackerRank