What is Multikey file organization?
What is Multikey file organization?
Multikey File Organization: When a file records are made accessed based on more than one key are called as Multikey file organization. Generally these files are index sequential file in which file is stored sequentially based on primary key and more than one index table are provided based on different keys.
What is hashing file organization?
Hashed file organisation is also called a direct file organisation. In this method, for storing the records a hash function is calculated, which provides the address of the block to store the record. Hash function is applied to columns or attributes to get the block address. The records are stored randomly.
What is physical file organization?
File organization refers to the relationship of the key of the record to the physical location of that record in the computer file. A physical file is a physical unit, such as magnetic tape or a disk. A logical file on the other hand is a complete set of records for a specific application or purpose.
What does index file contain?
An indexed file contains records ordered by a record key . A record key uniquely identifies a record and determines the sequence in which it is accessed with respect to other records.
What is sequential organization in English?
A sequential pattern of organization is similar to a chronological pattern, but arranges information according to a step-by-step sequence that describes a particular process. Using a sequential pattern, each main section of information represents a main step that one would follow in the actual process.
Where are sequential files used?
Sequential files are used to create programs, store reports, and to communicate with facilities outside of GT.
What is a hashed file organization what are its advantages and disadvantages?
Advantages of Hash File Organization Records need not be sorted after any of the transaction. Hence the effort of sorting is reduced in this method. Since block address is known by hash function, accessing any record is very faster. Similarly updating or deleting a record is also very quick.
What is hash file in Datastage?
The data in Datastage can be looked up from a hashed file or from a database (ODBC/ORACLE) source. Lookups are always managed by the transformer stage. A Hashed File is a reference table based on key fields which provides fast access for lookups. They are very useful as a temporary or non-volatile program storage area.
What are the file organization methods?
Types of file organization are as follows:
- Sequential file organization.
- Heap file organization.
- Hash file organization.
- B+ file organization.
- Indexed sequential access method (ISAM)
- Cluster file organization.
What is file .write the difference between logical and physical file?
A physical file can have a keyed sequence access path. This means that data is presented to a program in a sequence based on one or more key fields in the file. Logical files do not contain data. They contain a description of records found in one or more physical files.
What does an index file do?
An indexed file is a computer file with an index that allows easy random access to any record given its file key. The key must be such that it uniquely identifies a record. The indexes are created with the file and maintained by the system.
What is a multi key file organization?
This technique is used to sort a file based on multiple key values. Multi key file organization allows access to a data file by several different key fields. Example: Library file that requires access by author and by subject matter and title.
What is a sequentially organized file system?
In a sequentially organized file records are written consecutively when the file is created and must be accessed consecutively when the file is later used for input (figure 2). In a sequential file, records are maintained in the logical sequence of their primary key values.
What are the four fundamental file organization techniques?
The four fundamental file organization techniques that we will discuss are the following: 1. Sequential 2. Relative 3. Indexed sequential 4. Multi-key There are two basic ways that the file organization techniques differ. First the organization determines the file’s record sequencing, which is the physical ordering of the records in storage.
What is the difference between file organization and record sequencing?
First the organization determines the file’s record sequencing, which is the physical ordering of the records in storage. Second, the file organization determines the set of operation necessary to find particular records. Having particular values in search-key fields typically identifies individual records.
