Hapinoy:Database Group

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Week 1 Activities

  1. Daniel Lutz emailed Ron Rioux for the PowerPoint presentation which conains some of the functional requirements for the Hapinoy project. The requirements that are indicated in the slides have been added, along with an objective, to the Requirements Analysis Document.
  2. Mike Williams has found a way to access a trial version of ArcGIS. It is available at ArcGIS Trial Account Information. Ron Rioux's PowerPoint also indicates that the shapefiles which depict the Hapinoy store locations can be displayed using Mapserver.

Week 2 Activities

Skype Meeting

Scheduled: 6:30pm on Sunday, April 17

Find out what the file extensions mean
- from Wikipedia


A shapefile is a digital vector storage format for storing geometric location and associated attribute information. This format lacks the capacity to store topological information. The shapefile format was introduced with ArcView GIS version 2 in the beginning of the 1990s. It is now possible to read and write shapefiles using a variety of free and non-free programs.

Shapefiles are simple because they store primitive geometrical data types of points, lines, and polygons. These primitives are of limited use without any attributes to specify what they represent. Therefore, a table of records will store properties/attributes for each primitive shape in the shapefile. Shapes (points/lines/polygons) together with data attributes can create infinitely many representations about geographical data. Representation provides the ability for powerful and accurate computations.

While the term "shapefile" is quite common, a "shapefile" is actually a set of several files. Three individual files are mandatory to store the core data that comprises a shapefile: ".shp", ".shx", ".dbf", and other extensions on a common prefix name (e.g., "lakes.*"). The actual shapefile relates specifically to files with the ".shp" extension, but alone is incomplete for distribution, as the other supporting files are required.

There are a further eight optional files which store primarily index data to improve performance. Each individual file should conform to the MS DOS 8.3 filename convention (8 character filename prefix, period, 3 character filename suffix such as shapefil.shp) in order to be compatible with past applications that handle shapefiles, though many recent software applications accept files with longer names. For this same reason, all files should be located in the same folder.

Mandatory files :

  • .shp — shape format; the feature geometry itself
  • .shx — shape index format; a positional index of the feature geometry to allow seeking forwards and backwards quickly
  • .dbf — attribute format; columnar attributes for each shape, in dBase IV format

Optional files :

  • .prj — projection format; the coordinate system and projection information, a plain text file describing the projection using well-known text format
  • .sbn and .sbx — a spatial index of the features
  • .fbn and .fbx — a spatial index of the features for shapefiles that are read-only
  • .ain and .aih — an attribute index of the active fields in a table or a theme's attribute table
  • .ixs — a geocoding index for read-write shapefiles
  • .mxs — a geocoding index for read-write shapefiles (ODB format)
  • .atx — an attribute index for the .dbf file in the form of shapefile.columnname.atx (ArcGIS 8 and later)
  • .shp.xml — geospatial metadata in XML format, such as ISO 19115 or other schemas
  • .cpg — used to specify the code page (only for .dbf) for identifying the character encoding to be used

In each of the .shp, .shx, and .dbf files, the shapes in each file correspond to each other in sequence. That is, the first record in the .shp file corresponds to the first record in the .shx and .dbf files, and so on. The .shp and .shx files have various fields with different endianness, so as an implementor of the file formats you must be very careful to respect the endianness of each field and treat it properly.

Shapefiles deal with coordinates in terms of X and Y, although they are often storing longitude and latitude, respectively. While working with the X and Y terms, be sure to respect the order of the terms (longitude is stored in X, latitude in Y).

Week 3 Activities

MySQL Data Types

Our team has checked to see if MySQL supports any kind of media file as a data type that can be used in a MySQL database, but we have only found options for text, numbers, and time.

Our next step is to find out how we can use these possible data types to point towards a specific media file contained in another location. A row pertaining to a Hapinoy store might be able to contain references to other files and folders that can be read from and the field could simply locate the file, instead of being the file.