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ADVANTAGES of INDEXED FILES
1. Quite easy to process,
2. With proper selection of a key field, records in a large file can be searched and accessed in very quickly.
3. Any field of the records can be used as the key. The key field can be numerical or alphanumerical.
DISADVANTAGES of INDEXED FILES
1. Extra data structures have to be maintained (the COBOL run-time modules take care of these and it is not the programmers' concern). These extra data structures maintained on the disk can use up much disk space, especially for long key values.
2. The indexed files have to be reorganized from time time to get rid of deleted records and improve performance that gets gradually decreased with addition of new records.
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Advantages of Flat file database?
You should have the answer not me
What is difference between relative file and indexed sequential file?
Relative:- 1. In this mode the content of the program counter is added to the address part of the instruction to obtain the effective addressed. 2. Effective Address = Contents of the program counter + contents of address field. 3. No extra index bit is used. 4. Example:- EA = [ BX ] + [ SI ] + disp. EA = [ BX ] + [ DI ] + disp. Indexed:- 1. In this mode of addressing an attempt is made to avoid the use of two addressed for an operand. 2. Effective Address = Address field + contents of the specified - index registers. 3. In this extra index bit is used. 4. Example:- EA = [ BX ] + [ SI ] EA = [ BX ] + [ DI ]
Is direct access file ordered?
A direct access file, in most systems, refers to a file where individual records are retrieved directlly by using a record number to refer to a specific position in a file. The alternative is to reach the desired record by sequential access: Reading all the records from the beginning until you reach the desired position in the file. The records in the file do not have to be in any specific order.
File accessing techniques in data management system?
Information is kept in files. Files reside on secondary storage. When this information is to be used, it has to be accessed and brought into primary main memory. Information in files could be accessed in many ways. It is usually dependent on an application.Sequential Access: A simple access method, information in a file is accessed sequentially one record after another. To process the with record all the 1-1 records previous to 1 must be accessed. Sequential access is based on the tape model that is inherently a sequential access device. Sequential access is best suited where most of the records in a file are to be processed. For example, transaction files.Direct Access: Sometimes it is not necessary to process every record in a file. It may not be necessary to process records in the order in which they are present. Information present in a record of a file is to be accessed only if some key value in that record is known. In all such cases, direct access is used. Direct access is based on the disk that is a direct access device and allows random access of any file block. Since a file is a collection of physical blocks, any block and hence the records in that block are accessed. For example, master files. Databases are often of this type since they allow query processing that involves immediate access to large amounts of information. All reservation systems fall into this category. Not all operating systems support direct access files. Usually files are to be defined as sequential or direct at the time of creation and accessed accordingly later. Sequential access of a direct access file is possible but direct access of a sequential file is not.Indexed Sequential Access: This access method is a slight modification of the direct access method. It is in fact a combination of both the sequential access as well as direct access. The main concept is to access a file direct first and then sequentially from that point onwards. This access method involves maintaining an index. The index is a pointer to a block. To access a record in a file, a direct access of the index is made. The information obtained from this access is used to access the file. For example, the direct access to a file will give the block address and within the block the record is accessed sequentially. Sometimes indexes may be big. So hierarchies of indexes are built in which one direct access of an index leads to info to access another index directly and so on till the actual file is accessed sequentially for the particular record. The main advantage in this type of access is that both direct and sequential access of files is possible.
criteria for classifying computer files?
Criteria for Computer file classification Criteria for classifying computer files are: By nature of content: refers to the nature of file content By organization method: refers to the way files are arranged e.g. serial, sequential, random etc.
What is a indexed sequential file?
An indexed sequential file is a type of file organization where data records are stored sequentially in the order of key values. An index is maintained to help locate records quickly. This combination of sequential storage and indexing allows for efficient access to data in both sequential and random access patterns.
What are the advantages and disadvantages of indexed-sequential file organization?
Advantages of indexed-sequential file organization include efficient access to records through an index and sequential storage for faster retrieval. However, disadvantages may include increased complexity in managing the index and potential performance degradation due to index maintenance overhead.
What is the 3 diff methods of organizing file?
Sequential, Relative, Indexed.
Implementation of index sequential file organization?
Indexed sequential file organization. =In indexed sequential file organization, the records arestored in sequence according to a primary key and an index is created to allow random access of the file. This type of organization also allows the file to be accessed sequentially. Indexed sequential is the most commonlyused type of file organization. writer-k.k.b -montanna
What is the difference between the file maintenance and file organization?
file organization is of 3 types sequential,direct and indexed sequential where how data is accessed in eash file is decided where as file maintainence is
What is sequential file organization indexed sequential file organization?
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What are the disadvantages of indexed sequential file organization?
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Advantages of sequential file in c?
You don't have to bother with positioning in the file.
What are Different types of file organisation in DBMS?
Heap file organization Sequential File Organization Hashing File organization
What is difference between sequential file and index file?
the index file is more sicurity checked and contains more information about the acess . for example 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. If more than one index is present the other ones are called alternate indexes.The COBOL language supports indexed files with the following command in the FILE CONTROL section. however a sequential file isA file that contains records or other elements that are stored in a chronological order based on account number or some other identifying data. In order to locate the desired data, sequential files must be read starting at the beginning of the file. A sequential file may be stored on a sequential access device such as magnetic tape or on a direct access device such as magnetic disk. Contrast with random-file.Read more: sequential-fileContent of sequential file can't be accessed directly while index file content can be accessed directly through pointer. Sequential file is time consuming in comparison with index file.Example: Index of book - index fileExample: Bundle of plates - sequential file
What are the advantages and disadvantages of sequential file?
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What are the advantages and disadvantages of sequential file organizations?
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