what is really a flat text file?

[stakeMyHeart]

im a total newbie and i dont get this:

i dont get this flat text file my professor is talking about. I read from wikipedia that:
A "flat file" is a plain text or mixed text and binary file which usually contains one record per line[2] or 'physical' record (example on disc or tape). And i dont get it.

Then my professor said:
shingles technique assumes the input is a flat text file. Parse trees and symbol tables are generally not flat text files.

so what's that? what is a not flat text file?

i really need help on this. please help me. enlighten my mind.

[Narue]

what is a not flat text file?

CSV is an example of a flat file. XML is an example of a non-flat file.

[vadriaan]

A flat file is a file that contains a set of records. The records are normally seperated from each other by a space, a comma, or a new line. You could export a spreadsheet file to a comma seperated list i.e. a text file where every item is seperated by a comma. You can reasd this type of file with a text editor

A not flat file is a file where the records are organized with an index (this is a simplified explanation). The index will then point to the actual location of the record. You would normally need some application like a database management system to read this type of file.

[rubberman]

A flat file is a file that contains a set of records. The records are normally seperated from each other by a space, a comma, or a new line. You could export a spreadsheet file to a comma seperated list i.e. a text file where every item is seperated by a comma. You can reasd this type of file with a text editor

A not flat file is a file where the records are organized with an index (this is a simplified explanation). The index will then point to the actual location of the record. You would normally need some application like a database management system to read this type of file.

A non-flat file can also be a structured file, such as indicated by Narue's mention of XML as such an example. Indexes are not necessary for such.

[Rashakil Fol]

A flat text file could have an index too. You can't be too strict about these sorts of definitions.

[rubberman]

A flat text file could have an index too. You can't be too strict about these sorts of definitions.

True enough. I worked on MCBA manufacturing accounting software years ago that used flat files for the database, along with indexes to speed random access to the data.

[vadriaan]

The presence of an index in a flat file confused me, so here is what Wikipedia has to say:
Strictly, a flat file database should consist of nothing but data and, if records vary in length, delimiters. More broadly, the term refers to any database which exists in a single file in the form of rows and columns, with no relationships or links between records and fields except the table structure.

[stakeMyHeart]

CSV is an example of a flat file. XML is an example of a non-flat file.

what is CSV?

[Narue]

what is CSV?

Comma Separated Values. Google it for more details.

[stakeMyHeart]

thanks everybody for all your help and time :)