Data-Selector.

Hints & Tips.

There are three Data-Selector program files , these are called DataV18c ( for the Series 3 classic ) , DataV18a ( for the 3a ) DataV18s ( for the Siena )only one of these is required . The Series 3 version will run on either the Series 3,3a or Sienna ( in ' widescreen ' mode ! ) , the 3a version will only run on the 3a and the Siena version will run on the 3a or the Siena . Copy which ever version you require to an \App\ directory on any disk on your Psion and then from the system screen press Psion+I to install the program ( see your user guide if you are not sure how to do this - the section New Applications in the chapter called System Screen explains all ! ) . Once installed the Data-Selector icon will appear along with a list of availiable databases underneath it .

To start Data-Selector simply highlight the appropriate database name ( under the Data-Selector icon ) and press 'Enter' . The first time a database is opened you will be asked if you would like to create a permanent index for that file , if you are not short of memory it is recommended that you have a permanent index for all files ( an index of 250 records will be approx. 1k and so for 2000 records will be approx 8k ) if you have one very large file and lots of smaller files then you may like to have an index for the largest database and not for the smaller ones . The advantage to creating a permanent index is that file access from within Data-Selector will be quicker than if no index exists , this has most effect on larger databases and is why it is recommended for thse files with a large number of records . There are three possible answers to the question 'Create permanent index ', these are , Yes ( an index will be created , stored and used each time the file is opened ) , No ( which means I do not wish to create an index now but may wish to later - in this case each time you open this file you will be asked if you have changed your mind and would now like an index ) and Never ( I do not want an index now and don't bother asking ever again ! ) . If you change your mind about an index press Psion+K ( Series 3 ) or Shift+Psion+I ( 3a + Siena ) , this gives you the option of altering the current index options , pressing this will automatically delete the current index if it exists . If you then chose a different option than the current one the appropriate action will be taken . After the index options have been set you will see the message 'Opening file...' this will shortly be followed by 'Loading index...' ( this is the WORKING index and must be loaded for Data-Selector to work , it is not the permanent index . If you have chosen to create a permanent index this will be created at this time and will be used NEXT time the program requires it ) after a short delay the main display will appear , this consists of three windows , the left one will show the field names ( if using DataV17c for the Series 3 the first time the file is opened this will show Field1 , Field2 ..... Field6 , press Psion+T to edit these ) and the right one the data , blank fields are not shown nor are the field names of blank fields . The word wrap cannot be turned off ( it took me two weeks to get the word wrap to work correctly so you'll have it and like it !!! ) . If the text dissappears off the bottom of the screen press the lefthand arrow to scroll the text up ( the right scrolls down and 'Tab' returns the screen to normal ) this will only work if the text cannot all be shown in the normal size window . The third window will show the current record number and the total number of records ( IE 'Record 35 of 692' ) after you have performed a search this will also show the search text ( IE 'Search mark' ) on the Series 3 the time will also be displayed here , 3a users will have noticed that a status window is shown with the time shown here ( Control+Menu sets the type of status window or turns it off - the status window ALWAYS returns when the file is re-opened ) there is no clock or status window on the Siena version - sorry !

Moving through the records is easy , press the down arrow ( or Psion+N ) for the next record , up ( Psion+P ) for the previous or Psion+L for the last , Shift+Psion+F for the first . Pressing down or Psion+N whilst on the last record will move you to the first and if on the first record pressing up or Psion+P will move to the last . Psion+J allows you to jump to the record position you enter , this is the position in the CURRENT selection so if you have performed a search you may find that you do not get the record you might have expected . It is possible to show the records in a 'Page view' format , this is selected by pressing Psion+V ( or on the 3a + Siena the Diamond key ) The column widths can be altered by pressing Psion+W , the widths relate to the approximate number of characters that will be displayed ( in the default font ) in the relevant column . As in the record view if the text moves off the screen you can use the left and right keys to scroll the screen - this time to the left and right - again the 'Tab' key returns the screen to normal . The Next/Previous up/down move through the records as before except that you now move a page at a time .

As you'd expect with a program called Data-Selector you have a choice of ways of selecting the data you require . The first of these is 'Find from all' - Psion+F , as suggested this searches ALL records in the current database for the text entered . Once the search has been completed those records which match the search text will become the current selection . The second way of searching is 'Find from selected' Psion+G , this will only search the current selection ( not all records in the database - unless ,of course, the current selection does include all records in which case use Psion+F ) again once the search has been completed those records found will be the current selection . To return to all records in the database use 'Find all' Psion+A . The third search option is called 'Insta-search' to start this simply type the search text on the keyboard (the text must be entered within 10 seconds or so ) after the 10 second delay Insta-search will seek the next record that provides a match with the search text . You can search for the next matching record by pressing 'Enter' and for the previous matching record with Shift+'Enter' ( the current search text will be displayed in the information window ) . The way that Insta-search operates can be customised by pressing Psion+I  you can set the field to search ( this can be set to any of the first six fields or 'ALL' ) , if only search start of field is set to 'Yes' then the search text must match the corresponding number of characters in the first characters of the record being searched ( IE searching for 'Mark' would match 'marked' but not 'remarked' ) you can also select whether to start the search at the next record or always at the first record ( pressing 'Enter' or Shift+'Enter to find the next/previous matching record will ALWAYS start at the next/previous record , overriding this setting - it will not override the other two settings )

To close the current database and open a new one press Psion+O , to merge two files press Psion+M this will add the file to be merged to the end of the current database , to copy the current selection to a new file - Psion+C and to erase the current selection Psion+H . Psion+X exits Data-Selector and saves all current options . records can be added Psion+E , deleted Psion+D and updated Psion+U ( the last two only whilst in the record view ). New files can only be created from the system screen , place the highlight on any file name underneath the Data-Selector icon and press Psion+N . If you do create a new record this way , you will not be able to sort it . If you wish to be able to sort a file , create it using the built in Data program and then open it in DataSelector .

The 3a + Siena versions can alter the size of font to use with Psion+Z and Shift+Psion+Z

It is possible to sort records , they can be sorted alphabetically or numerically . If you wish to perform a numeric sort you must set the field containing the numerical data to sort by , if this field is not wholly numeric you will be given the option of setting another numeric field . The sort is very slow on large files ( IE above 500 records ) . The 3a + Siena versions have a 'Super Sort' facility which cuts the speed by two thirds ( it only works on the alphabetic search ) sadly due to differences in the operating system it does not work on the Series 3 so it has the old slow sort . When sorting large files on the 3a + Siena you may find that the message 'Out of memory - reducing index size' appears a few times , this is normal and despite these retrys the sort will still be far faster than the usual OPL style sort routine ( as shown in the programming manual ). It is now possible to sort on a date field , this operates in the same way as the numeric sort except that you have to select the required date field . The date format MUST be DD/MM/YY or D/M/YY . IE 29/07/1998 or 29/7/98 would be acceptable . 29-07-1998 will NOT work nor would 29\07\98 or 29/July/1998 .

Limitations.

Data-Selector has the following limitations . A maximum of six fields can be displayed . As with all OPL database programs the maximum size of any one record can be no greater than 1022 characters if a database has a record greater than this then a 'Record too large' error will occur . Data-Selector is unable to modify the field names , any alterations you make to the field names are stored in the options file for that database - if you then view the data in a different database program the original field names will be shown .

Data-Selector stores the options for the current file in an options file , this will be created by using the first and last letter of the database file name followed by '_optns' so if you opened a file called 'Phone' the options file would be called 'Pe_optns.opd' ( and will be found in the \OPD\ directory ) the temporary working index created as the database file is opened , and the permanent index if this option is selected , will also be named in the same way ( this time called 'Pe_t_idx.opd' and 'Pe_index.opd' ) . The astute amongst you will see that if you have another database file called 'Pete' then Data-Selector will try to use the same options and index files as 'Phone' - the obvious answer to this is to ensure that no database file begins and ends with the same letter ( if we re-name 'Pete' to 'Petes' this will neatly get around this little problem - unless you have a database file called 'Pickles' that is ! )