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Database Packages

 
  
 
Figure  3-4.—Examp1e  of  a  printed  spreadsheet. when  the  price  changes  and  direct  the  computer  to recalculate the totals/subtotals. Many   of   the   available   spreadsheet   software packages will interact directly with other programs such as  database  and  word  processing  applications.  Some spreadsheet  packages  integrate  (or  combine)  several programs  into  one,  such  as  a  spreadsheet  program,  a graphics   program,   and   a   database   management program. DATABASE PACKAGES Before we get too involved in database packages, let us first define what a database is. The term  database conjures   up   different   images   for   different   people. However, the concept is about as nontechnical and easy to envision as a filing cabinet full of file folders. The filing  cabinet  and  its  contents  are  the  database.  The ability   to   retrieve   the   data   and   calculate   statistics quickly  and  easily  without  regard  to  which  folder  or drawer  contains  the  information  makes  the  database system much more powerful than a comparable filing cabinet  system. Let’s   consider   a   simple   database,   one   which contains  information  about  all  enlisted  personnel  at your command in paygrades El through E6, including their  NECs.  First,  you  must  establish  a  record  in  the database  for  each  individual.  Conceptually,  you  can think of it as a file folder containing information on one particular  individual. You  have  one  file  folder,  or record,  for  each  individual  in  your  database.  In  this case, we want to know the individual’s name, rate, social security  number  (SSN),  division,  and  any  NECs  the individual currently holds. Once you have defined the record, you then proceed to establish fields for each of the data elements. In this example the fields are name, rate, SSN, division, and NECs.   If   you   assume   each   individual   can   have   a maximum  of  four  NECs,  you  would  have  a  database containing eight fields, as shown in figure 3-5. You now proceed to create the database by establishing the fields, specifying   their   size   and   the   type   of   information (numeric, alphanumeric, or logical) they can contain. Then, you enter the information for each individual into the  appropriate  fields. Once  it  is  created,  you  can arrange the database in some logical order (by NAME, SSN, and so on). The database is normally stored on some  type  of  secondary  storage  medium  (usually  disk), where the information is simply held until you need it. Now, suppose you wanted a list of the E-5 and E-6 Storekeepers in the supply department with an NEC of 1234. Under a manual system, you would have to open and search through each individual’s file folder-there could be hundreds! You would look at various entries; first,  for  rate  (or  the  rate  field  in  your  database  file); then,  in  order  to  see  if  this  person  is  assigned  to  the supply  department  (the  division  field).  You  would  then check to see if this person has an NEC of 1234 (the four NEC fields). Finally, you would have a stack of folders for all E-5 and E-6 Storekeepers who are assigned to the supply department and who have an NEC of 1234. You could  then  list  the  names  from  the  file  folders  (the records) selected. Depending upon the number of folders you have to look through, the entire evolution could take hours to complete. On the other hand, you could use one of the many database packages available to obtain the same answer.  The  database  application  program,  by  knowing the fields in each record and the content of each field, can  easily  search  for  this  information  in  a  matter  of seconds. You simply specify the selection criteria and the report format; the software does the rest—searches Figure  3-5.—Example  of  a  database  record. 3-11

   


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