Shareware Overload/ShartewareOverload.cdr/database/edb21.zip/EDB.DOC

Text File | 1991-04-03 | 14KB | 263 lines

                                      EDB
                                Ed's Data Base

                            Copyright 1991 Ed Hand


         This file is in two sections.  The first deals with the use of
    EDB.EXE.  The second section goes into detail on the format of the
    form file and how to write your own form files.


    Section One: How to get around in EDB


         EDB is a database whose format is defined by an ascii form file.
    The form file has an extension of ".frm".  The fields of a form can
    contain simple static information for display or accept any format of
    input.

         Execution of EDB is simple.  The name of the form file is given
    on the command line with no other arguments.  For example:

             EDB PHOTO

         This will start EDB and try to open a file named "PHOTO.FRM".
    If the file cannot be found in the current directory EDB will issue
    an error and halt execution.  If the file is successfully opened then
    EDB will read the form description, draw the screen and then allow
    you to start processing.  To run EDB the only files needed are the
    executable EDB.EXE and a form file.

         Once EDB has been started you will see a working screen.  You
    will stay at this screen for the entire program.  All commands are
    available from an options menu at the top of the screen.  There are
    several ways to select a command.  You may use the arrow keys to move
    the cursor around to the different commands.  Or for most commands
    you may simply enter the first letter of the command and EDB will
    move the cursor to that command.  The only exception to this is the
    compress command.  To move to the compress command enter the letter
    "O", the second letter of the word.  Once the command is highlighted
    press enter to select the command.  Users of emacs can also use
    standard emacs cursor commands to move the cursor:

             Cntrl-P and Cntrl-B move to the previous command.

             Cntrl-F and Cntrl-N move to the next command.

    Note that the emacs commands only work on the options menu.  If you
    are editing a field and enter a control character it will be entered
    as part of the data.  More on that later.  From the options menu you
    may also use Cntrl-R or Cntrl-L to redraw the screen.  This is useful
    if an ill behaved TSR pop-up doesn't repaint the screen upon exit.

         The EDB options commands are as follows:

             Exit - Exit the current session and return to the dos
                     prompt.

             Add - This function places the user in the first field of
                     the form and accepts data until the user exits the
                     form.   The data is then stored as the next entry in
                     the database.  If the specified database file does
                     not exist then EDB will issue an error and toss the
                     entered data.  If a database does not exist the add
                     function does NOT try to create it.

             Create - This option is used to create a new database file.
                     The cursor will be placed in the form at the
                     location of the field used to hold the filename.
                     After the user provides a filename EDB will create a
                     file of the form <filename>.EDB and put a standard
                     EDB header on the file.  This option must be used
                     before an add may be performed.  If the named file
                     already exists then EDB will not create the new
                     database file.

             Search - This option puts the user in the form and lets him
                     enter data into any/all/none of the fields.  After
                     the user exits the form any fields that had data
                     entered in them will be used for search criteria.
                     The only field that requires a value to be entered
                     is the field that holds the database file name.  If
                     the rest of the fields are left blank then all rows
                     will be found.

             Modify - After a search has completed, the retrieved data
                     may be modified with this command.  The user will be
                     placed in the form and allowed to edit any field
                     desired.  If the user edits the name of the database
                     file then EDB will try to add the entry to the newly
                     named file, if it exists.  If it writes the entry to
                     the new file then it will also set the delete bit on
                     the entry in the old file.

             Next - Moves to the next row found by search or find.

             Previous - Moves to the previous row found by search or
                     find.

             Delete - This row will set the delete bit for the current
                     record.  It will first ask for confirmation before
                     marking the record as deleted.

             Report - This row will prompt for a file name and then write
                     a copy of each record in the current search list to
                     the file.  If no file name is given EDB will default
                     to <formname.RPT>.  There are two choices for the
                     format of the report.  You may select either a comma
                     separated list or a file with one line for each
                     field using a "<field prompt>: <data value>" format.

             Compress - This option will compress a database file by
                     removing all entries with the delete bit set.  It
                     does this by creating a temporary file and reading
                     all non-deleted entries to that file.  Upon
                     successful completion EDB will then rename the old
                     database to <filename.old> and rename the temporary
                     file to <filename.EDB>.  Thus if there are any
                     errors during the compression the original file will
                     be left intact and in place.

             Find - This option is the same as search with one exception.
                     This command will find matching entries even if they
                     are marked as deleted.

             Undelete - This is the opposite of delete.  If a row is
                     deleted by mistake or for any reason needs to be
                     made active after a deletion this option will clear
                     the delete bit for that row.  The find command must
                     be used to locate a deleted row since search ignores
                     deleted records.

         When entering data into fields EDB requires that a carriage
    return be entered for the data to be accepted.  To exit a form the
    user must enter an escape character as the first character in a
    field.  If the user enters ANY character after a normal displayable
    character in a field, that character will be accepted as data.  To
    exit a form the user must enter a carriage return to get to the next
    field if any data has been entered in the current field.  Then an
    escape may be entered to keep the data or a CNTRL-C may be entered to
    cancel the current operation.


    Section Two: Form File Syntax


         The form file is a simple ascii file that describes how to draw
    the screen.  Any form of white space may separate the fields in the
    form file.  A form field description may contain several fields in
    the form file.

         The first field of the file is a single integer.  This is the
    number of form fields described in the file.  The rest of the file
    describes the actual fields of the database.

         There are six different types of form fields.  Each form field
    definition starts with a letter that identifies that fields type.
    The letters are "a", "d", "i", "l", "D", and "T".

         After the identifying character each field description is
    followed by an x and y coordinate value.  These two values tell EDB
    were on the screen to put the first character of the fourth parameter
    of the field.

         The fourth parameter is a quoted text string.  In most cases
    this string acts as a prompt for the field.  In one case this string
    is just static information to display at some point on the screen.
    If you don't want a prompt then define this as a null field (ie. "").

         Some fields require a fifth parameter.  This is a data type
    parameter.  It tells what kind of data the field holds.  Valid
    values for this option are:
             i   -   An integer value.  All integers are stored as a 32
                     bit value in the database.
             f   -   A floating point value.  All floating point numbers
                     are stored as doubles.
             s   -   A string.  Strings are stored at whatever length the
                     field is defined to be, padded if needed.

         The sixth parameter, for fields that need it, is the field length.
    It defines the number of characters allocated on the screen for a
    field.

         Please examine the sample form files delivered with this product
    for examples on how to implement a form file.  The syntax for each
    field type follows.

         Type = a
             Syntax - a <x> <y> <"prompt"> <data_type> <length>
                 This is a special field.  There may be only one in any
                 form.  Each time you add a new record to a database with
                 this field in the form, this field will automatically
                 increment.  This field must be of data_type integer.
                 When modifying records created with a form using this
                 field, this field may not be modified.

         Type = d
             Syntax - d <x> <y> <"prompt"> <data_type> <length> [places]
                 This is a standard data field.  Most fields in a form
                 will be of this type.  These fields can have a data_type
                 of integer, floating point, or string.  If this field
                 has a data_type of floating point then you must also
                 specify the number of decimal places to display on the
                 screen.  Otherwise the "places" parameter is left blank.

         Type = i
             Syntax - i <x> <y> <"text">
                 This is a static information field.  It is used to place
                 a string of text on the screen that will not change.  It
                 is useful for placing a name over a subsection of a
                 form.

         Type = l
             Syntax - l <x> <y> <"prompt">
                 This is a location field.  It is used to hold the name
                 of the database file to use.  The idea here being that
                 the same form can be used with several files.  Note
                 however, when doing a search or find only one filename
                 can be used.  Searching of multiple files is planned as
                 a future feature.  Each form may contain only one
                 location field.

         Type = D
             Syntax - D <x> <y> <"prompt">
                 This is a date field.  It holds a four byte structure
                 that is a date.  If the first and only character entered
                 in this field is a "T", then EDB will return the current
                 date.  The way the date is displayed is dependent on
                 your country code.  If you don't have country.sys
                 running or country is set to U.S. then the date is
                 displayed as "mm/dd/yy".  The date will display as
                 "dd/mm/yy" for european users and as "yy/mm/dd" for
                 asian user if country.sys is properly installed.  Please
                 note that you must enter a date in the same format it is
                 displayed in or EDB will get confused.  At this time
                 there is no check to insure a valid date.

         Type = T
             Syntax - T <x> <y> <"prompt">
                 This is a time field.  It is identical to the date field
                 but holds a time stamp instead.  As with the date field,
                 a "T" will return the current system time.

         Now for the limiting factors.

         No more than thirty-two fields per form.

         No more than one screen per form.  In other words, your form
    cannot be more than eighteen lines long.  However, this is something
    I plan to change in the future.

         The suggested working area for the screen is from lines six
    through twenty-three inclusive.  And columns two through seventy-nine
    inclusive.

         Well, if you find any bugs or problems let me know.  Also if you
    have any suggestions or ideas feel free to send them to me also.

         My INTERNET address is:

                 [e-mail]