access.introduction Introductory/Access: Verbs


Command access.introduction Introductory/Access: Verbs
Applicable release versions: AP, R83
Category Access: Verbs (152)
Description a Pick facility to retrieve and output data.

Access is an original piece of the Pick System and is made up of the List pre-processor (the oldest), the Select processor, and the Output processor.

Access is a system-level information retrieval language that allows users to query their data base without writing complex programs.

Access uses TCL commands as verbs and displays the results either on terminals or printers. An Access verb operates on specified files and items based on various optional criteria, specifications, modifiers, limiters, and options.

Often described as an-ad hoc data query language, the greatly expanded dictionary capabilities of Advanced Pick offer the possibility of real nonprogrammer access to the data base.

Access, used in conjunction with the Update processor ("UP"), makes Advanced Pick the most accessible data management system in existence.

Additional Advanced Pick features enhance the already comprehensive query language. Pick/BASIC and FlashBASIC calls from dictionaries are used for complex data calculations and output formatting. The "ss" (spread sheet) connective allows printing out Access reports in spread-sheet format. This is achieved by adding the "ss" connective to the sort sentence and defining the desired range parameters.

Use of b-tree indexes has increased the speed and performance of Access. See "b-tree" in see.also.

Access commands are entered at TCL and thus can be recalled, modified, or executed through utilization of the TCL-stack. Access sentences may also be stored and invoked through macros, menus, procs, FlashBASIC and Pick/BASIC (using the "execute" statement).

An Access statement has the following form: verb file.reference {item.list} {selection criteria} {sort criteria} {output specifications} {print limiters} {modifiers} {(options)}

The verb and file.reference are required as operator and operand respectively. The verb must be the first word of a TCL command.

All other elements are optional and are used to modify either the operator, operand, or output. Selection criteria, sort criteria, output specifications, print limiters, and modifiers follow the item.list and may be in any order. Options, if used, must be placed last and must be preceded by a left parenthesis. The right parenthesis is optional.

Relational operators may be used with any of the elements of Access sentences to allow exact specification of the conditions to be met.

"file.reference" is the name of a file in the "md" to which the user is currently logged. It can also be a synonym file name, or "q-pointer". The file name can be preceded by the literal "dict" to Access the dictionary of the file instead of the data portion of the file. The default is data. In some cases, data may be specified to indicate only the data portion of the file.

To reference a file in another account or md from TCL, pathnames or q-pointers may be used. The pathname may be used in place of the in any TCL or Access statement.

A pathname may be entered in one of the four following forms:,,,,,

",," is the fully qualified form, specifying all elements of the path.

",," defaults the to the same as the

"," defaults the to the current account.

"" defaults the to the current account and the to the same as the

The following form references a master dictionary, defaulting to: mds,,,

Commands requesting a destination or source with a "to:" or "from:" prompt, such as "copy" and <ctrl>+cp (cut and paste from a specified item), expects an item-id (or itemlist), or a file.reference, or a file.reference and item-id. To name a path or file, the file.reference must be preceded by a parenthesis.

"itemlist" specifies one, some, or all item-ids in the file defined by the associated file.reference. The item.list may be: one or more explicit item-ids, a series of items separated by relational operators, an asterisk (*) to represent all the items in the file, or null. If a list is not active, a null item-id implies a new item for UP and all items for the other processors. To cause a processor to use the active list, the item.list must be null. An item-id with the same name as a language element in either the md or the dictionary of the file must be enclosed in single quotes.

An active list can be used by another "select" statement to narrow down the resulting list. A list can be passed to another list until a "save-list" or any other Access, TCL2, or Pick/BASIC verb is invoked. For example:

select entity with state = "ny"

n items selected.
select entity with city = "syracuse"

m items selected.
list entity name city state phone

The above series of statements first selects all entites in the state on new york, and out of these selects all entites in syracuse and then outputs a columnar report.

"selection criteria" limits the data by specifying criteria that must be met. Multiple criteria may be established to limit data selection to meeting a certain set of limitations. These sets are established by the logical relational connectives "and" or "or".

"sort criteria" are used to define the sort operation.

"output specifications" specifies the attributes to list. The selected attribute items or synonym labels are displayed in either a columnar or non-columnar format depending on the report width. The width of the report is the sum of the width of each attribute to be listed plus one blank separator between each attribute. If the width of the report does not exceed the page width as set by the "term" verb, a columnar format is generated. The attributes for each item are displayed one under the other. If the requested output exceeds the page width, the column headings are listed in a non-columnar format down the side of the output with their respective values immediately to the right. In the non-columnar format, the column headings are listed only if there is a corresponding value.

The item-id is always displayed unless it is suppressed using the "id-supp" connective or unless it is suppressed using the "i" option on the output-macro attribute of the associated file-defining item (AP only).

"print limiters" suppress the listing of attributes within an item that do not meet specified limits.

"modifiers" control listing parameters such as double-spacing ("dbl-spc"), control breaks ("roll-on" or "break-on"), column totals ("total"), and suppression of item-ids ("id-supp"), automatic headings ("hdr-supp" or "col-hdr-supp"), and default messages ("ni-supp").

"(options)" are used to tell the processor about special handling and tend to be processor specific. The options are single alpha characters and/or a numeric range specification as required by the specific processor.

Command results are reported to the terminal unless the "p" option is used to direct output to the Spooler. They are usually preceded by a left parenthesis, except in the case of spooler options. At this time, the right parenthesis is optional at the end of the option specification. When used, options must be the last element on the command line. See the "see.also" attribute for a listing of Access verbs.

On 6.1 releases and above, tabbed output is possible by modifying the master dictionary item. See the "tabbed.output" token for more information.
Related access.verbs