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Below are some technical tips for Release 4 that you may find useful. A new tip will be posted at least once a month. If you have a technical tip you would like to see included here, please email us! To determine that a secondary index is being used with a jQL statement, trace output will be produced by setting the following environment variables prior to running the jQL statement: JDIAG=TRACE=INDEX A recent addition to the jBC SYSTEM() function on Release 4 is SYSTEM(1035). This function returns the type of license currently in force for this particular user session. The possible license types returned by this function are:
1 =
Enterprise In jBASE 4, the Keyboard Independence subroutines CommandInit and CommandNext have been renamed to JBASECommandInit and JBASECommandNext respectively.
jBASE has
gone to great lengths to make Release 4's functionality unified on all
platforms, which means functionality that only existed on UNIX platforms now
works on Windows. This makes porting your jBASE application to different
operating systems nearly painless. The most advantageous of these are
background processing and record locking (jRLA). The big payoff with jRLA is that locks can be taken on directory files. Plus, jRLA makes it easy to see what is going on because it updates an internal hashed table managed by jBASE. Because locks are hashed into groups, jRLA locks are faster than OS locks and performance will not degrade when there are a large number of locks. The functionality provided by JBASE_WARNLEVEL on 3.x has been implemented in a different fashion on Release 4. This was a design decision to make the behavior of the runtime more flexible and consistent at the same time. Instead of a global setting handling all conditions, there are now settings for individual error messages according to a bit mask. For example, we are all familiar with the well-known error message: Non-numeric value -- ZERO USED. If you set (or export) JBASE_ERRMSG_NON_NUMERIC=3, you will not get this error message and the program will not drop into the debugger. The other handy environment variable, to handle the condition where a BASIC program encounters an unassigned variable, is JBASE_ERRMSG_ZERO_USED. The bit masks available for these environment variables are as follows:
1
- Don't print the error message
jBASE Release 4.1
introduced COL.HDG, CNV and FMT to allow for
complete
command line dictionary manipulation. Often when working on jQL reports you may want to work with a smaller portion of the data to test the layout, breaks and totals. jBASE provides for "sampling" the data in two different forms. Sample a known number of items (in this case 100) SORT CUSTOMER BY NAME BY CITY NAME ADDR1 ADDR2 CSZ SAMPLE 100 Sample the data taking every nth item (in this case 1 of every 100) SORT INVOICE WITH DATE >= "01/01/04" BY CUST BY DATE BREAK-ON CUST DATE TOTAL INV.AMT SAMPLED 100
Not all Unix/Linux users
realize that jBASE commands can be used without the actual need to "login" to
jBASE. This can be accomplished with a
"minimum environment".
With this simple process you can use any jBASE command from any user environment
with permissions to access jBASE. (This could also be included in the
etc/profile) One of the greatest aspects of the jBASE database is the jQL (reporting) flexibility for those coming from other MultiValue databases. jBASE supports legacy PICK A type dictionaries complete with F and A correlatives and also supports simultaneously the newer D type dictionaries and I - correlatives. What many do not know is: We auto display fields for LIST/SORT if sequential numeric DICTS exist (1-nnn) We support PH DICTS where a DICT called DEMOGS has field 1 = PH , 2 = NAME ADDRESS PHONE would display NAME ADDRESS and PHONE by doing a LIST CUSTOMER DEMOGS A combo where DICT named 1 has field 1 = PH and 2 = NAME etc. and then LIST CUSTOMER would use the PHrase NAME ADDRESS PHONE and display those fields. jBASE allows different types of forms to be attached to a printer. These types are controlled by the SP-TYPE command. The SP-TYPE command instructs jBASE to read the jspform_"TYPE" file from the config directory and apply the attributes included in that file to all print jobs for printers using that TYPE. The config item jspform_deflt is used if no other TYPE is defined. Look at the $JBCRELEASEDIR/config/jspform_deflt item to see the many options you can set including WIDTH, DEPTH, STARTJOB, ENDJOB and others. Copy the jspform_deflt to jspform_TYPE where TYPE is whatever you want to define and change the settings for that form type. In jBASE Release 4, you can create a datalevel file called OBJECT for your BP files and the $ items will then be put there instead of in the actual BP file. This makes it much nicer to LIST the BP files since the $ item which contains non-printable characters will no longer exist in the BP data file. Simply "CREATE-FILE DATA bpfilename,OBJECT modulo" and all subseqent BASIC bpfilename will place the $ items in bpfilename,OBJECT. In Release 4 of jBASE, the ability exists to create a data-section only file without having to create the dictionary, nor is the dictionary required to exist prior to creating the file. One of the goals of Release 4 is to unify the functionality between Unix type systems and Windows. For example, Windows now supports jRLA, which means you can now READU lock files in directories. Another example is background processing. No longer do you need to run the 'jstart' command; Windows now supports all of the background commands that were previously only available on Unix, like PH-START, PH-STATUS, and Z.
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