An ordered Sequential file, is a file ordered upon some key field. The ordering of the records in the file makes it possible to process an ordered file in ways that are not available to us with unordered files. While it is not really possible to apply batch updates or deletes to an unordered file these are possible with ordered files.


Inserting records into an ordered Sequential file.


To add records to an ordered file a major consideration is to preserve the ordering. This means that the record must be inserted into the file in the correct position. It can't just be added to the end of the file as it can with unordered files.

As with all changes to ordered Sequential files we can't just insert the records into the existing file. To insert records into the file we have to create a new file that contains the inserted records.
To read a sequential file:

1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.
2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by Yash , an ibibo Master, at 9:32 AM on July 01, 2008

An ordered Sequential file, is a file ordered upon some key field. The ordering of the records in the file makes it possible to process an ordered file in ways that are not available to us with unordered files. While it is not really possible to apply batch updates or deletes to an unordered file these are possible with ordered files.


Inserting records into an ordered Sequential file.


To add records to an ordered file a major consideration is to preserve the ordering. This means that the record must be inserted into the file in the correct position. It can't just be added to the end of the file as it can with unordered files.

As with all changes to ordered Sequential files we can't just insert the records into the existing file. To insert records into the file we have to create a new file that contains the inserted records.
To read a sequential file:

1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.
2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by Shobhit , an ibibo Master, at 5:57 PM on June 25, 2008

An ordered Sequential file, is a file ordered upon some key field. The ordering of the records in the file makes it possible to process an ordered file in ways that are not available to us with unordered files. While it is not really possible to apply batch updates or deletes to an unordered file these are possible with ordered files.


Inserting records into an ordered Sequential file.


To add records to an ordered file a major consideration is to preserve the ordering. This means that the record must be inserted into the file in the correct position. It can't just be added to the end of the file as it can with unordered files.

As with all changes to ordered Sequential files we can't just insert the records into the existing file. To insert records into the file we have to create a new file that contains the inserted records.
To read a sequential file:

1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.
2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by Raksha , an ibibo Master, at 9:35 AM on June 24, 2008

An ordered Sequential file, is a file ordered upon some key field. The ordering of the records in the file makes it possible to process an ordered file in ways that are not available to us with unordered files. While it is not really possible to apply batch updates or deletes to an unordered file these are possible with ordered files.


Inserting records into an ordered Sequential file.


To add records to an ordered file a major consideration is to preserve the ordering. This means that the record must be inserted into the file in the correct position. It can't just be added to the end of the file as it can with unordered files.

As with all changes to ordered Sequential files we can't just insert the records into the existing file. To insert records into the file we have to create a new file that contains the inserted records.
To read a sequential file:

1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.
2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by Madhurima , an ibibo Master, at 6:03 PM on June 13, 2008

An ordered Sequential file, is a file ordered upon some key field. The ordering of the records in the file makes it possible to process an ordered file in ways that are not available to us with unordered files. While it is not really possible to apply batch updates or deletes to an unordered file these are possible with ordered files.


Inserting records into an ordered Sequential file.


To add records to an ordered file a major consideration is to preserve the ordering. This means that the record must be inserted into the file in the correct position. It can't just be added to the end of the file as it can with unordered files.

As with all changes to ordered Sequential files we can't just insert the records into the existing file. To insert records into the file we have to create a new file that contains the inserted records.
To read a sequential file:

1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.
2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by Ashish Yadav , an ibibo Wizard, at 6:43 PM on June 10, 2008

well blogger01, An ordered Sequential file, is a file ordered upon some key field. The ordering of the records in the file makes it possible to process an ordered file in ways that are not available to us with unordered files. While it is not really possible to apply batch updates or deletes to an unordered file these are possible with ordered files.


Inserting records into an ordered Sequential file.


To add records to an ordered file a major consideration is to preserve the ordering. This means that the record must be inserted into the file in the correct position. It can't just be added to the end of the file as it can with unordered files.

As with all changes to ordered Sequential files we can't just insert the records into the existing file. To insert records into the file we have to create a new file that contains the inserted records.
To read a sequential file:

1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.
2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by kishore , an ibibo Master, at 9:03 PM on June 09, 2008

well blogger01, An ordered Sequential file, is a file ordered upon some key field. The ordering of the records in the file makes it possible to process an ordered file in ways that are not available to us with unordered files. While it is not really possible to apply batch updates or deletes to an unordered file these are possible with ordered files.


Inserting records into an ordered Sequential file.


To add records to an ordered file a major consideration is to preserve the ordering. This means that the record must be inserted into the file in the correct position. It can't just be added to the end of the file as it can with unordered files.

As with all changes to ordered Sequential files we can't just insert the records into the existing file. To insert records into the file we have to create a new file that contains the inserted records.
To read a sequential file:

1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.
2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by Romi , an ibibo Master, at 4:10 PM on June 09, 2008

Hi there

Sequential file techniques provide a straightforward way to read and write files

the best reason for using sequential files is their degree of portability to other programs, programming languages, and computers. Because of this, you can often look at sequential files as the common denominator of data processing, since they can be read by word-processing programs and editors (such as PowerBASIC's), absorbed by other applications (such as database managers), and sent over the Internet to other computers.

The idea behind sequential files is simplicity itself: write to them as though they were the screen and read from them as though they were the keyboard.

Create a sequential file using the following steps:

1. Open the file in sequential output mode. To create a file in PowerBASIC, you must use the OPEN statement. Sequential files have two options to prepare a file for output:

OUTPUT: If a file does not exist, a new file is created. If a file already exists, its contents are erased, and the file is then treated as a new file.

APPEND: If a file does not exist, a new file is created. If a file already exists, PowerBASIC appends (adds) data at the end of that file.

2. Output data to a file. Use WRITE# or PRINT# to write data to a sequential file.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

To read a sequential file:

1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.
2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.
3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by Reeta K , an ibibo Master, at 2:38 PM on June 09, 2008

An ordered Sequential file, is a file ordered upon some key field. The ordering of the records in the file makes it possible to process an ordered file in ways that are not available to us with unordered files. While it is not really possible to apply batch updates or deletes to an unordered file these are possible with ordered files.


Inserting records into an ordered Sequential file.


To add records to an ordered file a major consideration is to preserve the ordering. This means that the record must be inserted into the file in the correct position. It can't just be added to the end of the file as it can with unordered files.

As with all changes to ordered Sequential files we can't just insert the records into the existing file. To insert records into the file we have to create a new file that contains the inserted records.

The animation below demonstrates how records are inserted into an ordered Sequential file.




Self Assessment questions








The main processing loop from the animation is shown below. Examine the code in this program fragment and then attempt to answer the questions below.

PERFORM UNTIL EndTF AND EndMF
IF TFKey < MFKey
MOVE TFRec TO NFRec
WRITE NFRec
READ TF etc.
ELSE
IF TFKey > MFKey
MOVE MFRec TO NFRec
WRITE NFRec
READ MF etc.
END-IF
END-IF
END-PERFORM

Answered by Sharad Singh , an ibibo Master, at 2:09 PM on June 09, 2008

Hi,


Create a sequential file using the following steps:

1. Open the file in sequential output mode. To create a file in PowerBASIC, you must use the OPEN statement. Sequential files have two options to prepare a file for output:

OUTPUT: If a file does not exist, a new file is created. If a file already exists, its contents are erased, and the file is then treated as a new file.

APPEND: If a file does not exist, a new file is created. If a file already exists, PowerBASIC appends (adds) data at the end of that file.

2. Output data to a file. Use WRITE# or PRINT# to write data to a sequential file.

3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

To read a sequential file:


1. First, OPEN the file in sequential INPUT mode. This prepares the file for reading.

2. Read data in from the file. Use PowerBASIC's INPUT# or LINE INPUT# statements.

3. Close the file. The CLOSE statement closes a file after the program has completed all I/O operations.

Answered by Ajay Pal , an ibibo Master, at 9:58 AM on June 09, 2008