FILE AND DATA MANAGEMENT
FILE TYPES
When data is saved, they are stored in a file, which different software application save in different ways(types).
Here are some file types :
Text : .txt : Stores plain text without any formatting and is useful for transferring data between application, but any formatting will be lost.
Comma separated value : .CSV : stores structured data as plain text in rows with each columns separated by commas. it is useful for transferring data between databases and spreadsheet or other applications which require data in structured format.
Rich text format : .rtf : stores text-based documents and includes the formatting(rich text).
Microsoft word XML document : .docx : stores m’s word processing in open XML format by saving all objects separately within a compressed file.
Portable document format : .pdf : used to share read only documents that can be accessed by any PDF reader software. Now commonly used for storing documents in the web as its content can be indexed by search engines.
Open document text : odt : open-source file type for word processor documents and can be opened by open-source word processing software and is not tied to one manufacturer.
Open document spreadsheet : .ods : open-source file type for spreadsheet documents and can be opened by open-source spreadsheet software and is not tied to one manufacturer.
Open document Presentation : .odp : open-source file type of presentation that is used by open-source presentation software and is not tied to one manufacturer.
Hypertext markup language : .html : stores web pages that can be opened by any web browser.
Extensible markup language : .xml : file that uses markup language to define objects and their attributes. Used to transfer data between application and can be rad by simple text editor.
Audio video interleave : .avi : Microsoft’s method of storing video files with very little compression. file sizes are big but no data is lost.
moving pictures experts group(MPEG) layer-4 : .mp4 : audio and video are compressed and videos can be shared across the internet.
Waveform audio file format : .wav : stores audio file as waveform data and enables different sampling rates and bit rates. This is the standard format for audio CDs but does not include compression so files are large.
MPEG layer-3 audio compression : .mp3 : stores audio file ina compressed format approximately 10% the size of .wav files, enabling the audio to be shared across the internet.
Bitmap image : .bmp : Stores imager as uncompressed rarter images, storing each pixel individually. Large files but can be accessed by any software.
Joint photographic experts group : .jpg : stores images as compressed raster images, mostly used by digital cameras and is a common format for web graphic but it uses lossy compression meaning the quality can be lost.
Portable network graphic : .png : compressed raster image and can include background transparency colours making it useful when the images are required on different colour background.
Scalable vector graphic : .svg : stores image as 2D vector graphics. it is a standard format for using vector graphics on the web.
Executable program file : .exe : Stores program object code which enables the program to be executed by the computer.
FILE MANAGEMENT
Knowing your format :
Proprietary file format are file types that have been developed by software manufacturers solely for use within their software. Open-source file formats are file types that have been developed for the purpose of being used by any proprietary software or open-source software. Generic file format enable data to be transferred between software-won’t include any formatting i.e. CSV or TXT.
Knowing file access :
Indexed sequential access - many years ago, data was often stored on a tape which required records to be written one after another onto the tape, it is also accessed the same, storing the data serially and accessing it serially. Therefore it would take a long time to access a needed file from it because you need to read the whole file from the beginning to get into required data/record.
Direct file access - records are stored in random order with no sequence. When storing a file, a hashing algorithm(calculation) is performed on the key field to determine the the storage address where the record should be stored-and when you need the record, the same calculation is put to search for it.
Hierarchical database management system - was created in 1960s and is not commonly used today. It relies on a tree structure which deals with one-to-many relationship and can only work in one direction.
MANAGEMENT INFORMATION SYSTEMS
A management information system (MIS) provides summary information to managers to enable them to make decisions. This additional software collates data from more than one database and interconnect the data form those databases to produce reports/charts that analyse all the data together- this is called executive information system.