Personal Computer World 1997 September/Personal_Computer_World_Sep_97.iso/DXRS/SLIPCW09.DXR/00017_databasehandlers.ls

Text File | 1997-06-27 | 5.5 KB | 192 lines

on dbfind me, afield, operator, criteria
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  if objectp(tableinstance) = 1 then
    mSetIndex(tableinstance, "primeidx")
    mSelect(tableinstance)
    mSetCriteria(tableinstance, afield, operator, criteria)
    mSelect(tableinstance)
    set howmanyselected to mSelectCount(tableinstance)
    mGoFirst(tableinstance)
    set foundlist to list()
    repeat with i = 1 to howmanyselected
      append(foundlist, mGetField(tableinstance, afield))
      if i < (mSelectCount(tableinstance) + 1) then
        mGoNext(tableinstance)
        next repeat
      end if
      exit repeat
    end repeat
  else
    put "no tableinstance object found"
  end if
  mSetIndex(tableinstance, "primeidx")
  mSelect(tableinstance)
  return foundlist
end

on dbclosesession me
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  if objectp(table) = 1 then
    put "object table exists"
    set table to EMPTY
    put "table object instance now  = " & objectp(table)
  else
    put "no object found"
  end if
  if objectp(database) = 1 then
    put "object table exists"
    set database to EMPTY
    put "database object instance now  = " & objectp(database)
  else
    put "no object found"
  end if
  if objectp(tableinstance) = 1 then
    put "object tableinstance exists"
    set tableinstance to EMPTY
    put "tableinstance object instance now  = " & objectp(tableinstance)
  else
    put "no object found"
  end if
  if objectp(dbinstance) = 1 then
    put "object table exists"
    set dbinstance to EMPTY
    put "dbinstance object instance now  = " & objectp(dbinstance)
  else
    put "no object found"
  end if
  updateStage()
end

on dbgo me, whichrecord
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  if objectp(tableinstance) = 1 then
    mSetIndex(tableinstance, "primeidx")
    mSelect(tableinstance)
    if value(whichrecord) <= totnumrecs then
      mGo(tableinstance, whichrecord)
    else
      put "maximum record encountered at " & totnumrecs
      mGo(tableinstance, totnumrecs)
    end if
  else
    put "no tableinstance object found"
  end if
end

on dbcount me
  global database, table, dbinstance, tableinstance
  set totnumrecs to 0
  if objectp(tableinstance) = 1 then
    mSetIndex(tableinstance, "primeidx")
    mSelect(tableinstance)
    set totnumrecs to mSelectCount(tableinstance)
  else
    put "no tableinstance object found"
  end if
  return totnumrecs
end

on dblistfields me, table
  global database, table, dbinstance, tableinstance
  set listfields to list()
  if objectp(dbinstance) = 1 then
    set layout to mDumpStructure(dbinstance)
    set lineCount to the number of lines in layout
    repeat with i = 1 to lineCount
      if line i of layout contains "-field" then
        set thisfieldname to EMPTY
        repeat with j = 1 to the number of chars in line i of layout
          if charToNum(char j of line i of layout) = 39 then
            set characternumber to j
            exit repeat
          end if
        end repeat
        repeat with k = characternumber + 1 to the number of chars in line i of layout
          if charToNum(char k of line i of layout) <> 39 then
            set thisfieldname to thisfieldname & char k of line i of layout
            next repeat
          end if
          exit repeat
        end repeat
        append(listfields, thisfieldname)
      end if
    end repeat
  else
    put "dbinstance object does not exist"
  end if
  return listfields
end

on dbnext me
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  if objectp(tableinstance) = 1 then
    mGoNext(tableinstance)
  else
    put "tableinstance object does not exist"
  end if
end

on dbgetfield me, fieldName
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  set fieldcontent to EMPTY
  repeat with i = 1 to count(listfields)
    if getAt(listfields, i) = fieldName then
      if objectp(tableinstance) = 1 then
        set fieldcontent to mGetField(tableinstance, fieldName)
        next repeat
      end if
      put "tableinstance object does not exist"
    end if
  end repeat
  return fieldcontent
end

on dbopensession me
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  if (objectp(database) <> 1) and (objectp(table) <> 1) then
    set database to xtra("v12dbe")
    put database
    set table to xtra("v12table")
    put table
  else
    put "objects already exist" & database & table
    return 0
  end if
  updateStage()
end

on dbuse me, dbName, thepassword, tableName
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  if (objectp(database) = 1) and (objectp(dbinstance) <> 1) then
    set dbinstance to new(database, the pathName & dbName, "readonly", thepassword)
    put dbinstance
  end if
  if (objectp(table) = 1) and (objectp(tableinstance) <> 1) then
    set tableinstance to new(table, mGetRef(dbinstance), tableName)
    put tableinstance
  end if
  if objectp(dbinstance) = 1 then
    set totnumrecs to dbcount(me)
    set listfields to dblistfields(me, dbName)
  end if
end

on dbprevious me
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  if objectp(tableinstance) = 1 then
    mGoPrevious(tableinstance)
  else
    put "tableinstance object does not exist"
  end if
end

on dbselectall me
  global database, table, dbinstance, tableinstance, totnumrecs, listfields
  if objectp(tableinstance) = 1 then
    mSetIndex(tableinstance, "primeidx")
    mSelect(tableinstance)
  else
    put "tableinstance object does not exist"
  end if
end