Shareware Grab Bag/Shareware Grab Bag.iso/003/pbase.arc/PBASE.DOC

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                                            PREFACE

          Welcome to pBASE!

          pBASE is a "programmable" Data Base Management System (DBMS) featuring a
          fourth generation language.

          This is an EVOLUTIONARY system... you can help by suggesting changes and
          enhancements... your feedback is essential.  For example, the following
          should be available in the next version:

               - improved color support (SET COLOR ...)

               - report enhancements (XTAB, etc.)

               - improved argument editing

               - program (.PRG) generator

               - improved debugging and error facilities (messages and ONERROR)

               - additional functions

          The following are possible LONG term additions:

               - form and report screen "painter"

               - C language interface to DBMS engine

               - long text or memo field support with integrated editor

               - C and/or PASCAL code generation

               - SQL ALTER TABLE

               - Naive user interface






          ----- NOTICE ----- NOTICE ----- NOTICE ----- NOTICE ----- NOTICE -----

          THIS DOCUMENTATION PACKAGE IS INCOMPLETE AND WAS EXTRACTED FROM VERSION 1 OF
          THE pBASE USER MANUAL.  THE COMPLETE DOCUMENTATION AND CURRENT VERSION OF
          pBASE IS AVAILABLE FOR A NOMINAL FEE.

          THE POWER AND FLEXIBILITY OF pBASE IS BEST DEMONSTRATED BY REVIEWING THE
          SAMPLE PROGRAMS IN CONJUNCTION WITH THE DOCUMENTATION (sic).

          ----- NOTICE ----- NOTICE ----- NOTICE ----- NOTICE ----- NOTICE -----
















                                  TTTaaabbbllleee   ooofff   CCCooonnnttteeennntttsss


                1. Introduction..........................................1
                   1.1. Disclaimer.......................................1
                   1.2. Overview.........................................2
                   1.3. Highlights.......................................2
                        1.3.1. Querying Data.............................2
                        1.3.2. Writing Reports...........................2
                        1.3.3. Application Programs......................2
                   1.4. Operational Requirements.........................3

                2. Quick Tutorial........................................4
                   2.1. Relational Model.................................4
                        2.1.1. Tables....................................4
                        2.1.2. Operations on Tables......................4
                        2.1.3. Data Types................................4
                        2.1.4. Indexes...................................4
                   2.2. Structured Query Language (SQL)..................5
                        2.2.1. Creating and Removing a Table.............5
                        2.2.2. Retrieving Table Data.....................5
                        2.2.3. Adding Table Data.........................5
                        2.2.4. Updating Table Data.......................6
                        2.2.5. Deleting Table Data.......................6
                        2.2.6. Creating and Removing an Index............6
                        2.2.7. Multiple Tables...........................6
                        2.2.8. The Catalog...............................6

                3. Reference Section.....................................7
                   3.1. How to Use the Reference Section.................7
                   3.2. Terminology......................................8
                        3.2.1. Special Symbols...........................8
                        3.2.2. Logical Operators.........................9
                        3.2.3. Arithmetic Operators.....................10
                   3.3. Reserved Words..................................11
                   3.4. Macros..........................................12
                        3.4.1. Basic Macro Substitution.................12
                        3.4.2. Program Argument Macros..................12
                        3.4.3. SQL Command "Bind" Macros................13
                   3.5. Memory Variables................................14
                   3.6. Application Commands............................15
                        3.6.1. *........................................18
                        3.6.2. :........................................19
                        3.6.3. ASSIGN...................................20
                        3.6.4. CANCEL...................................21
                        3.6.5. CLEAR LINE...............................22
                        3.6.6. CLEAR MESSAGE............................23
                        3.6.7. CLEAR SCREEN.............................24
                        3.6.8. CREATE WINDOW............................25
                        3.6.9. DOCASE...................................26

                                          i















                        3.6.10. DOMENU..................................27
                        3.6.11. DOREPORT................................29
                        3.6.12. DOWHILE.................................32
                        3.6.13. DROP FORM...............................33
                        3.6.14. DROP VARIABLE...........................34
                        3.6.15. DROP WINDOW.............................35
                        3.6.16. ENTER...................................36
                        3.6.17. FILECLOSE...............................37
                        3.6.18. FILECLOSE...............................38
                        3.6.19. FILEREAD................................39
                        3.6.20. FILEWRITE...............................40
                        3.6.21. FORM....................................41
                        3.6.22. IF......................................43
                        3.6.23. PAUSE...................................44
                        3.6.24. POSITION................................45
                        3.6.25. QUIT....................................46
                        3.6.26. RESET FORM..............................47
                        3.6.27. RESET REPORT............................48
                        3.6.28. RETURN..................................49
                        3.6.29. RUN.....................................50
                        3.6.30. SHOW ERROR..............................51
                        3.6.31. SHOW MESSAGE............................52
                        3.6.32. SHOW VARIABLE...........................53
                        3.6.33. SHOW (text).............................54
                        3.6.34. SOUND...................................55
                        3.6.35. STATUS SWITCH...........................56
                        3.6.36. STATUS VARIABLE.........................57
                        3.6.37. SUSPEND.................................58
                        3.6.38. SWITCH DEFAULT..........................59
                        3.6.39. SWITCH ECHO.............................60
                        3.6.40. SWITCH ERROR............................61
                        3.6.41. SWITCH STEP.............................62
                        3.6.42. SWITCH TALK.............................63
                        3.6.43. USE WINDOW..............................64
                        3.6.44. VERSION.................................65
                   3.7. Data Base Commands..............................66
                        3.7.1. CREATE CURSOR............................68
                        3.7.2. CREATE DATABASE..........................69
                        3.7.3. CREATE INDEX.............................70
                        3.7.4. CREATE TABLE.............................71
                        3.7.5. DELETE...................................72
                        3.7.6. DROP CURSOR..............................73
                        3.7.7. DROP DATABASE............................74
                        3.7.8. DROP INDEX...............................75
                        3.7.9. DROP TABLE...............................76
                        3.7.10. EXPORT..................................77
                        3.7.11. FETCH...................................78
                        3.7.12. IMPORT..................................79
                        3.7.13. INSERT..................................80

                                         ii














                        3.7.14. RESET DATABASE..........................81

                        3.7.15. SELECT..................................82
                        3.7.16. SET PRINT...............................83
                        3.7.17. SHOW....................................84
                        3.7.18. STATUS CURSOR...........................85
                        3.7.19. STATUS TABLE............................86
                        3.7.20. TEMPLATE PRINT..........................87
                        3.7.21. UPDATE..................................88
                        3.7.22. USE CURSOR..............................89
                        3.7.23. Predicate...............................90
                   3.8. Functions.......................................91
                        3.8.1. String Functions.........................91
                        3.8.2. Boolean Status Functions.................92
                        3.8.3. Status Functions.........................93
                   3.9. Form Processor..................................94
                        3.9.1. Commands.................................94
                        3.9.2. Programming with Forms...................95
                        3.9.3. Examples.................................97
                        3.9.4. Processing Individual Fields............103
                        3.9.5. Programming Shortcuts...................104
                   3.10. Report Writer.................................106
                         3.10.1. Commands..............................106
                         3.10.2. Runtime Execution.....................107
                         3.10.3. Simple Reports........................108
                         3.10.4. Professional-Looking Reports..........109
                                 3.10.4.1. Positioning with TAB and S..109
                                 3.10.4.2. Page Headings and Footings..110
                                 3.10.4.3. Element Formatting..........111
                         3.10.5. Summaries and Control Breaks..........113
                                 3.10.5.1. Counting Example............114
                                 3.10.5.2. Totaling Example............115
                                 3.10.5.3. Summary Example.............116
                         3.10.6. Cross-tabulations.....................117

                4. Appendices..........................................118
                   4.1. Error Messages.................................118
                   4.2. Limits.........................................126
                   4.3. Defaults.......................................127
                   4.4. Console Format.................................128
                   4.5. Backup (and Restore)...........................129
                   4.6. Catalog........................................130

                 Index.................................................131







                                         iii












                                          Introduction

          1. Introduction

          1.1. Disclaimer

          The information contained in this document is subject to change without
          notice.

          THE AUTHOR OR SUPPLIER MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS
          MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
          MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  The author or
          supplier shall not be liable for errors contained herein or for incidental
          or consequential damages in connection with the furnishing, performance or
          use of this material.

          This document contains proprietary information which is protected by
          copyright laws.  All rights are reserved.  No part of this document may be
          reproduced without the prior written concept of the author.

                              (C) COPYRIGHT 1985 4B Associates
































                                          1












                                          Introduction

          1.2. Overview

          pBASE is a "programmable relational data base management system designed for
          programmers. pBASE provides facilities for querying and manipulating data as
          well as report writing.

          pBASE represents all data as a table.  For example, a sample table of two
          rows and four columns:

               -----------------------------------------------------
               |CHK_NUMBER|DATE    |PAYEE               |AMOUNT    |
               |----------|--------|--------------------|----------|
               |1000      |01/02/85|Utility Company     |    123.45|
               |1001      |01/10/85|Grocery Store       |     66.77|
               -----------------------------------------------------

          1.3. Highlights

          1.3.1. Querying Data

          pBASE may be used to access data, using pBASE commands, without the need for
          user-written computer programs.  pBASE commands are available to:

               - select and update data

               - sort retrieved data in a specified sequence

               - do calculations using data values

          1.3.2. Writing Reports

          pBASE provides formatting commands that control how queried data is
          displayed.

          1.3.3. Application Programs

          pBASE provides commands to develop application programs.  Procedural and
          non-procedural commands control program logic flow and interface to external
          hardware devices.

          Commands may be stored in files and executed.










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                                          Introduction

          1.4. Operational Requirements

               IBM PC 256K or equivalent

               PCDOS 2.0+

               Hard disk preferred












































                                          3












                                         Quick Tutorial

          2. Quick Tutorial

          This section presents a quick introduction to pBASE.  It is a VERY basic
          tutorial on relational data base concepts.

          2.1. Relational Model

          pBASE utilizes the relational model of data. A RELATION is defined as a
          simple two-dimensional table having a specific number of columns and zero or
          more unordered rows.  Each row represents one entry in a table and
          corresponds to a record in a traditional file format.  Each row contains a
          value or NULL entry in each column.

          2.1.1. Tables

          2.1.2. Operations on Tables

          Many operations may be performed on a table and include:

               - Creating/droping tables

               - Retrieving data.  An entire table, row, or partial row may be
               retrieved.

               - Updating data.

               - Adding data.

               - Deleting data.

               - Combining of tables based on table content value.  This operation is
               called "joining."

          2.1.3. Data Types

          pBASE supports two data types:

               - NUMBER

               - CHARACTER

          2.1.4. Indexes

          pBASE also provides an indexing facility.  Indexes are NOT required to
          access data.  They may be used to improve the performance of accessing table
          rows.  A request to access or update data makes no explicit reference to an
          index.  pBASE always decides which indexes, if any, to use to satisfy a
          request.  Commands are provided to create and drop indexes.



                                          4












                                         Quick Tutorial

          2.2. Structured Query Language (SQL)

          pBASE is based on the STRUCTURED QUERY LANGUAGE (SQL).  pBASE is a non-
          procedural language because data access requests specify the desired
          results, not how to do it.

          pBASE commands consist of a command verb, one or more optional clauses,
          language keywords, and parameter operands.  The most common pBASE commands
          include:

               (retrieval)
                    SELECT         Fetches data from one or more tables

               (manipulation)
                    INSERT         Adds a new table row
                    UPDATE         Changes data in one or more table rows
                    DELETE         Deletes one or more table rows

               (definition)
                    CREATE TABLE   Defines a new table and it's column attributes
                    DROP TABLE     Removes a table
                    CREATE INDEX   Defines a table index (on a column)
                    DROP INDEX     Removes a table index

          2.2.1. Creating and Removing a Table

          Before data can be stored, updated, or retrieved, a table must be created.
          The CREATE TABLE command is used to create a table and define it's format.
          The command does not add a data to the table.

          2.2.2. Retrieving Table Data

          Retrieving data is the most common request of pBASE. The SELECT command is
          used to specify what data is to be retrieved.  The basic form of the SELECT
          command is:

               SELECT <data>
               FROM <table>
               WHERE <condition>

          2.2.3. Adding Table Data


          The INSERT command allows the user to pass a row of values to be placed into
          a table.  For example:

               INSERT INTO <table> (<column-list>) VALUES(<value-list>)




                                          5












                                         Quick Tutorial

          2.2.4. Updating Table Data

          The UPDATE command specifies which column(s) should be updated and on which
          rows the updating should take place.  For example:

               UPDATE <table> SET <column-name>=<value> ...

          A single UPDATE command can affect more than one row in a table and more
          than one field in those rows.

          2.2.5. Deleting Table Data

          The DELETE command specifies which rows should be deleted from a table.  The
          WHERE clause determines which rows are affected.  For example:

               DELETE FROM <table>
                 WHERE <predicate>

          2.2.6. Creating and Removing an Index

          Query and manipulation of tables can be handled by pBASE without any
          explicit specification from the user.  However, better performance is
          possible when indexes are defined for appropriate table columns.  For
          example:
               CREATE INDEX <index> ON <table> (<column-list>)

          The index is never referenced when using pBASE commands.  pBASE analyzes
          commands and indexes and uses the best access path to the table(s).

          2.2.7. Multiple Tables

          pBASE allows data stored in different tables to be combined.  This
          technique, called joining, causes pBASE to merge data from different tables
          and present the data.  (The merged data is not stored in the data base.)
          For example:

               SELECT <column-list> FROM <table>,<table> WHERE <predicate>


          2.2.8. The Catalog

          pBASE maintains several system tables that collectively "catalog" the
          contents of the database.  These tables contain information about objects
          that are of interest to the execution of the system itself.  Examples of
          such objects includes base tables, indexes, column types, column sizes, etc.
          Because the catalog itself consists of tables, just like ordinary user
          tables, a subset of pBASE commands may be used to view the contents of these
          tables.



                                          6












                                       Reference Section

          3. Reference Section

          3.1. How to Use the Reference Section

          This section contains the formal definition of all pBASE commands.  It
          includes:

               - the proper syntax

               - a definition

               - one or more examples

          The commands are subdivided by type, application and data base.  In
          addition, reserved words and terminology are listed and special features are
          covered in detail:

               macros, memory variables, functions, forms, report writer


          A typical example of command syntax is:

               SHOW ERROR '<text>'

          where capitalized words are pBASE keywords and lower case words are general
          terms for what should be entered.  Square brackets ([]) mean that anything
          within the square brackets is an optional entry.  Curly brackets ({}) mean
          that within the curly brackets there are two or more mutually exclusive
          items that may be entered.  The choices are separated by a vertical bar (|).

          pBASE keywords may NOT be abbreviated.

          Command lines may extend over several lines.  Lines may be continued by
          appending a semicolon (;) at the end of the line.  Continuation is valid in
          interactive and program modes.  For example:

               pBASE> SELECT column1,column2 FROM table;
               pBASE> WHERE column3>45;
               pBASE> ORDER BY column2,column1


          A literal string is indicated by enclosing the string in single (') or
          double (") quotation marks.








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                                Reference Section - Terminology

          3.2. Terminology


          3.2.1. Special Symbols


               <attribute> - an integer between 1 and 255

               <arguments> - a list of blank-separated identifiers

               <base-col> - a number between 1 and the maximum width of the display
               screen

               <base-row> - a number between 1 and the maximum depth of the display
               screen

               <border-type> - 1 (single line) or 2 (double line)

               <bottom-margin> - a number between 1 and the size of a printed page

               <column#> - a number between 1 and the width of a display screen or
               printed page

               <column-definition> - a list of comma-separated <column-name>  <column-
               type> pairs

               <column-name> - an identifier

               <column-type> - CHAR(<size>) or NUMBER

               <command-line> - a program name with optional trailing <arguments>

               <comment> - any meaningful <text>

               <constant> - a literal number or string

               <cursor#> - a number between 1 and maximum cursors

               <database-name> - 1-8 characters valid for a DOS filename

               <depth> - a number between 1 and maximum <depth>

               <expression> - an identifier or group of identifiers and operators
               whose value can be determined

               <field#> - a number between 1 and maximum fields

               <filename> - a valid DOS file specification



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                                Reference Section - Terminology


               <index-name> - an identifier name

               <line#> - a number between 1 and maximum lines

               <picture> - (see Reference Section - Report Writer Element Formatting)

               <predicate> - (see Reference Section - Predicate)

               <program-name> - a valid DOS file specification with a ".COM", ".EXE",
                    ".BAT" or ".PRG"

               <row#> - a number between 1 and maximum rows

               <skeleton> - a wildcard specification containing characters and "?"

               <table-name> - an identifier

               <template-file> - a DOS file with a ".TMP" extension

               <text> - any "printable" ascii characters

               <title> - string value

               <top-margin> - a number between 1 and the depth of a console screen or
                    printed page

               <variable-name> - an identifier

               <width> - a number between 1 and the width of a console screen or
               printed page

               <window#> - integer between 1 and maximum concurent windows

          3.2.2. Logical Operators

               (listed in order of precedence)

               ()   parentheses for grouping

               NOT  logical not (unary operator)

               AND  logical and

               OR   logical or






                                          9












                                Reference Section - Terminology

          3.2.3. Arithmetic Operators

               (listed in order or precedence)

               ()   parentheses for grouping

               *    multiplication

               /    division

               +    addition

               -    subtraction






































                                         10












                               Reference Section - Reserved Words

          3.3. Reserved Words

          The following "words" are reserved by pBASE.  They may NOT be used as memory
          variable names or identifiers:

          AND            ASC            ALL            AND            ASSIGN
          AT             BOOLEAN        BREAK          BY             CANCEL
          CASE           CHAR           CLEAR          COLOR          COLUMN
          CONCAT         CONSOLE        COUNT          CREATE         CURSOR
          DATABASE       DBRET          DEBUG          DEFAULT        DEL
          DELETE         DESC           DETAIL         DISPLAY        DOCASE
          DOMENU         DOREPORT       DOWHILE        DROP           ECHO
          EJECT          ELSE           END            ENDCASE        ENDIF
          ENDMENU        ENDONERROR     ENDREPORT      ENDWHILE       ENTER
          ERASE          ERROR          EXIT           EXPORT         FALSE
          FETCH          FIELD          FILECLOSE      FILEOPEN       FILEREAD
          FILEWRITE      FINAL          FOOTING        FOR            FORM
          FORMAT         GETDATE        GETENV         GETTIME        HEADING
          HORZ           IF             IMPORT         INDEX          INS
          INSERT         INTO           ISEOF          ISFEOF         ISFILE
          ISNUMBER       ISYES          KEY            KEYPRESS       LIKE
          LINE           LOCK           LOOP           MATCH          MENUCHOICE
          MENUOPTION     MENUTITLE      MENUTYPE       MESSAGE         NOT
          NULL           NUMBER         OFF            ON             ONERROR
          OR             ORDER          OTHERWISE      OUTPUT         PAGE
          PAUSE          PICTURE        POSITION       PRINT          PRINTER
          PROMPT         QUIT           READ           REP            REPORT
          RESET          RETURN         ROW            RUN            SCREEN
          SELECT         SET            SHOW           SKIP           SOUND
          STATUS         STEP           SUBCOUNT       SUBSTR         SUBTOTAL
          SUSPEND        SWITCH         SYSDATE        SYSOTHER       SYSPAGE
          SYSTIME        SYSTOTAL       TAB            TABLE          TALK
          TEMPLATE       TEXT           TO             TOLOWER        TOTAL
          TOUPPER        TRUE           UNLOCK         UPDATE         UPDPOS
          USE            VALUES         VARIABLE       VERSION        VERT
          WHERE          WIDTH          WINDOW         XTAB















                                         11












                                   Reference Section - Macros

          3.4. Macros


          3.4.1. Basic Macro Substitution


          Whenever an ampersand (&) followed by the name of a memory variable is
          encountered in a command, pBASE replaces the &<variable-name> with the
          string value of the variable.  If an ampersand is NOT followed by a valid
          memory variable name no substitution takes place (and the ampersand remains
          within the command line).

          Basic macros are very useful for dynamic modification of commands during the
          actual execution of pBASE programs.  They may also be used to pass
          parameters between programs.

          Example:

               pBASE> ENTER dest PROMPT 'Destination filename of output'
               pBASE> SET PRINT TO &dest     (at execution time this becomes
                                             "SET PRINT TO temp.prt" if "temp.prt"
                                             was entered in response to the ENTER
                                             command)


          3.4.2. Program Argument Macros


          A "special" form of the basic ampersand macro replacement facility is the
          program argument macro.  Whenever an ampersand followed by an integer number
          is encountered, pBASE replaces the ampersand and the number with the
          relative argument corresponding to the number.

          Example:

               pBASE> HELP CREATE                 (command HELP with argument CREATE)
               pBASE> IF TOUPPER('&1')='CREATE'   (At execution time within program
                                                  HELP.PRG this becomes:
                                                  "IF TOUPPER('CREATE')='CREATE'")
               pBASE>    SHOW 'CREATE argument'











                                         12












                                   Reference Section - Macros

          3.4.3. SQL Command "Bind" Macros


          A third form of macro substitution is a special case limited to
          specification of data base data manipulation command field values and exists
          to maintain compatibility with SQL programming conventions.  Whenever a
          colon (:) is encountered within a SQL data manipulation command, the colon
          and the concatenated memory variable name are replaced by the string value
          of the memory variable.

          Example:

               pBASE> UPDATE SUP SET item=:item,descr=':descr';
               pBASE> WHERE id=:id                (At execution time this becomes
                                                  "UPDATE SUP SET item=12,descr=
                                                   'Red box' WHERE id=1001" assuming
                                                  that memory variables item, descr,
                                                  and id contained "12", "Red box",
                                                  and 12 respectively)
































                                         13












                              Reference Section - Memory Variables

          3.5. Memory Variables


          Memory variables are temporary elements that are created and destroyed by
          commands.  pBASE memory variables do NOT have any notion of TYPE, such as
          numeric or character.  Their so-called type is implicit based on the content
          (value) and usage.

          Memory variables are used to contain constants, results of computations, and
          (macro) symbolic substitution strings.  Commands that manipulate memory
          variables include:

               ASSIGN <expression> TO <variable-name>

               DROP VARIABLE {<variable-name>|ALL|LIKE <skeleton>}

               ENTER <variable-name> PROMPT <text>

               EXPORT VARIABLE {ALL|LIKE <skeleton>} TO <filename>

               IMPORT VARIABLE FROM <filename>

               SHOW <variable-name>

               STATUS VARIABLE


























                                         14












                            Reference Section - Application Commands

          3.6. Application Commands

          Application commands support the development and execution of pBASE
          applications.  Also within this general framework are commands that provide
          operator assistance.  Following are application commands grouped
          functionally:

          Display:

               CLEAR LINE - Clear a display line

               CLEAR MESSAGE - Clear display message area

               CLEAR SCREEN - Clear entire display

               CREATE WINDOW - Open a window

               DROP WINDOW - Close a window

               ENTER - Enter value into memory variable

               DROP FORM - Remove form window

               FORM - Non-procedural forms data entry

               POSITION - Move display cursor to coordinates

               RESET FORM - Free form resources

               SHOW ERROR - Display error message

               SHOW MESSAGE - Display informational message

               SHOW (text) - Display text string

               USE WINDOW - Specify "current" window















                                         15












                            Reference Section - Application Commands

          File Input/Output:

               FILECLOSE - Close a DOS file.

               FILEOPEN - Open a DOS file.

               FILEREAD - Read a line into a memory variable.

               FILEWRITE - Write an expression.

          Memory Variables:

               ASSIGN - Assign the value of an expression to a memory variable

               DROP VARIABLE - Destroy a memory variable

               EXPORT VARIABLE - "Save" variable(s)

               IMPORT VARIABLE - "Restore" variable(s)

               SHOW VARIABLE - Display the value of a memory variable

               STATUS VARIABLE - Display status of memory variable pool


          Programming:

               * - Comment line

               : - DOS command

               CANCEL - Stop execution of program(s)

               DOCASE - Execute commands with one of several CASEs

               DOMENU - Non-procedural menu

               DOREPORT - Non-procedural report writer

               DOWHILE - Repeat while condition true

               IF - Execute commands when condition true

               PAUSE - Suspend execution temporarily

               RESET REPORT - Free report writer resources

               RETURN - Exit program

               RUN - Execute program

                                         16












                            Reference Section - Application Commands


               SUSPEND - Temporary interactive mode


          Other:

               QUIT - Exit pBASE

               SOUND - "Beep" the console.

               STATUS SWITCH - Display current switch status

               SWITCH DEFAULT - Reset all switches to their defaults

               SWITCH ECHO - Display executed commands ON|OFF

               SWITCH ERROR - Display errors ON|OFF

               SWITCH STEP - Single step execution ON|OFF

               SWITCH TALK - Echo command results ON|OFF

               VERSION - Display pBASE version




























                                         17












                             Reference Section - Data Base Commands


          3.7. Data Base Commands

          Data base commands either operate on a data base or provide operator
          assistance for data base related tasks.  Following are data base commands
          grouped functionally:

          Data Retrieval:

               EXPORT - Move table data to external DOS file

               FETCH - Retrieve SELECTed data into memory variables

               SELECT - Specify data to be queued for retrieval

               SHOW - Display queued data at console

               TEMPLATE PRINT - Template replacement report writer


          Data Manipulation:

               DELETE - Delete rows

               IMPORT - Move external DOS file data into a table

               INSERT - Add a row to a table

               UPDATE - Update table rows that satisfy condition


          Data Definition:

               CREATE DATABASE - Create an empty data base

               CREATE INDEX - Create a table column index

               CREATE TABLE - Create a table

               DROP DATABASE - Destroy an entire data base

               DROP INDEX - Destroy an index

               DROP TABLE - Destroy an entire table







                                         66












                             Reference Section - Data Base Commands

          Other:

               CREATE CURSOR - "Open" an access path to a data base

               DROP CURSOR - "Close" an access path to a data base

               RESET DATABASE - Drop all active cursors

               SET CURSOR - Specify current active cursor

               SET PRINT - Specify TEMPLATE PRINT output device

               STATUS CURSOR - Display cursor status

               STATUS TABLE - Display table(s) status




































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                                 Reference Section - Functions

          3.8. Functions


          Functions are special purpose operations that occur during run-time of a
          command.  A function performs a specific operation on the (sub)value of an
          expression.  A function does not occur alone, rather it appears with its
          related expression in the general form:

               FUNCTION([expression])

          Note that all start positions and offsets are relative to one (1).

          3.8.1. String Functions


               <concatenated-string> = CONCAT(<string1> <string2>)
                    Returns concatenation of string1 and string2.

               <modified-string> = DEL(<string> <count> <start>)
                    Returns substring of <string> after removing <count> characters at
                    position <start>.

               <date> = GETDATE()
                    Returns system date in mmddyy format.

               <string> = GETENV(<environment-name>)
                    Returns environment value.

               <time> = GETTIME()
                    Returns system time in hhmmss format.

               <modified-string> = INS(<string1> <string2> <start>)
                    Returns expanded string after inserting <string2> into   <string1>
                    at position <start>.

               <modified-string> = TOLOWER(<expression>)
                    Converts the expression to all lower case.

               <modified-string> = TOUPPER(<expression>)
                    Converts the expression to all upper case.

               <index> = MATCH(<string1> <string2> <start>)
                    Returns the <index> of where <string2> starts within <string1>
                    relative to <start>.

               <modified-string> = REP(<string1> <string2> <start>)
                    Returns modified string after replacing part of <string1> with
                    <string2> at <start>.



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                                 Reference Section - Functions


               <string> = SUBSTR(<expression> <start> <length>)
                    Extracts a substring of the specified starting position and
                    length.

          3.8.2. Boolean Status Functions



               <boolean> = ISEOF()
                    Returns TRUE if (data base) END OF FETCH else FALSE.

               <boolean> = ISFEOF()
                    Returns TRUE if END OF FILE else FALSE.

               <boolean> = ISFILE(<filename>)
                    Returns TRUE if <filename> exists else FALSE.

               <boolean> = ISNUMBER(<expression>)
                    Returns TRUE if <expression> is numeric else FALSE.

               <boolean> = ISYES(<text>)
                    Displays a menu prompt and returns operator response (TRUE or
                    FALSE).



























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                                 Reference Section - Functions

          3.8.3. Status Functions


               <return-code> = DBRET()
                    Returns the current data base status code.

               <key-value> = KEYPRESS()
                    Returns the last key pressed by operator.











































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                                         Form Processor

          3.9. Form Processor

          3.9.1. Commands

          Form processing commands specify what and when data field(s) are entered.
          Following are form processor commands grouped functionally:

          Form content:

               FORM FIELD - Entry field location and size

               FOR FOR TABLE - Default form text and fields

               FORM HEADING - Background text heading

               FORM SHOW FIELD - Display entry field

               FORM SHOW TEXT - Display background text

               FORM TEXT - Background text definition

          Form run-time:

               FORM CLEAR FIELD - Clear entry field to all blanks

               FORM ERASE FIELD - Remove entry field from console display

               FORM LOCK FIELD - Disallow data entry

               FORM READ FIELD - Read data

               FORM UNLOCK FIELD - Allow data entry

          Other:

               DROP FORM - Close form window

               RESET FORM - Free form resources

               FORM DELETE - Auto-DELETE

               FORM SELECT - Auto-SELECT

               FORM SELECT - Auto-SELECT

               FORM UPDATE - Auto-UPDATE





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                                         Report Writer


          3.10. Report Writer

          3.10.1. Commands

          Report writer commands specify how, what, and when the contents of a report
          are printed.  Their actual usage is very hierarchically structured and is
          graphically represented as follows:


               <Report-group> ::=
                    DOREPORT
                      REPORT XXXX
                        <Command-group>
                        END
                      ENDREPORT


               <Command-group> ::=
                     pBASE commands
                    <Report-group>
                    <Output-group> (REPORT OUTPUT only)


               <Print-group> ::=
                    TAB n
                    SKIP [n]
                    EJECT
                    <string> [PICTURE <picture>]
                    <variable-name> [PICTURE <picture>]
                    SYSDATE
                    SYSTIME
                    SYSPAGE


               <Output-group> ::=
                    TO { CONSOLE | PRINTER | <filename> }
                    PAGE FORMAT <depth><width><top-margin><bottom-margin>













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                                      Appendicies - Limits

          4.2. Limits


               string length - 255

               command line length - 510

               identifier length - 20

               DOCASE nesting - 10

               IF nesting - 10

               DOWHILE nesting - 10

               max table columns - 255

               max length CHAR column size - 255

               max precision NUMBER column type - 18 decimal digits

               max memory variables - 64

               Nesting of programs - 5

               Concurrent cursors - 5

               Screen size 25X80

               Forms - text, fields

               Menus - options - 9

               SELECT fields - 20

               Concurrent windows - 10















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          Appendicies - Catalog

          4.6. Catalog

          The pBASE catalog consists of system tables.  These tables are just like
          ordinary user data tables although access to them is somewhat restricted.
          The system tables consist of:

               SYSTABLES
               This table contains a row for every table in the data base.  For each
               table, it contains the table name, column count, creator, and
               authorization.

               SYSCOLUMNS
               This table contains a row for every table row in the data base.  For
               each such column, it gives the table name, column name, relative column
               number, column type and column length.

               SYSINDEXES
               This table contains a row for every index in the data base.  For each
               such index, it gives the table name, column name, index name, and
               creator.

               SYSUSERAUTH
               This table contains a row for each authorized data base user.  For each
               column, it gives the user identifier, password, and authorization.

          Since the catalog consists of tables, just like ordinary user tables, it can
          be queried (and reported) by means of the SELECT command just as ordinary
          tables can.  For example, to find out what table(s) contain an 'USERID'
          column:

               > SELECT tbname FROM syscolumns WHERE colname='USERID'

          Although the catalog tables can be queried with the SELECT command they
          CANNOT be updated with UPDATE, DELETE or INSERT commands.  Updating is
          limited to the DATA DEFINITION commands: CREATE/DROP table, CREATE/DROP
          INDEX, etc.















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