Leszynski naming convention

From HandWiki

The Leszynski naming convention (or LNC) is a variant of Hungarian notation popularized by consultant Stan Leszynski specifically for use with Microsoft Access development.[1] Although the naming convention is nowadays often used within the Microsoft Access community, and is the standard in Visual Basic programming, it is not widely used elsewhere.

The conventions are derived from an earlier set of conventions, the Leszynski/Reddick naming conventions, originally developed in 1992 by Greg Reddick. Eventually, Leszynski and Reddick had different ideas about how the conventions should be developed, and split into two separate sets of conventions, the other being the RVBA Conventions.

As in all Hungarian notations, it uses prefixes (called tags) to indicate the type of objects and database development fields. The general structure of Hungarian notation (named after Charles Simonyi's native country) is to break down object names into the following elements: [prefix(es)][tag]BaseName[Suffix/Qualifier] The tags are lower case and the object name is camel case. Spaces and underscores are not used.

Advantages

Since the Leszynski naming convention is a special form of Hungarian notation the same general advantages also apply to the Leszynski convention.

The use of distinctive prefixes makes your database self-documenting; when you see frmSales in VBA code, you will know that it references a form, and when you see curSales you will know that it is a Currency variable. When selecting a query from a drop-down list, you will know that a query starting with qmak is a make-table query, while one starting with quni is a union query. This information will allow you to avoid errors such as using the SetFocus method (a control method) with a field, or trying to open a table.

Disadvantages

  • Since the Leszynski naming convention is a special form of Hungarian notation the same general disadvantages also apply to the Leszynski convention.
  • Changes in database design may require wholesale renaming. For example, replacing a table with a query would involve either retaining the tbl name for the query, or going through the entire database replacing the tbl name with a query name.
  • When transferring the database to a different DBMS, problems will arise if the target DBMS does not support CamelCase names.
  • As every object of the same type starts with the same letter, it is not possible to navigate through the objects in a List box by typing the beginning letter.

Elements

The elements of the naming convention are described in the following table.

Component Description Example
Prefix(es) A lowercase letter that adds extra information to the tag p for Public variable
Tag A three-letter sequence indicating the object type tbl for table
BaseName A word or two describing the object. If several words are used, each starts with a capital letter, and there are no spaces between them OutlookContacts – contacts imported from Outlook
Suffix (RVBA), Qualifier (LNC) A word giving more specific information about an object ByDate – the data is sorted by date

The Basic LNC Object Prefixes

Object Tag
Incomplete objects, backup objects, or objects that are under development _ or – (In some versions of Access, dashes sort to the beginning of the database object list.)
Hidden system objects zh
Displayed system objects zs
Programmatically created temporary objects zt
Backup copies of objects, for later copying or reuse zz

The Basic LNC Variable Prefixes

Variable Type Tag
Local variable [no prefix]
Local static variable s
Module-level variable m
Public variable in a form or report module p
Public variable declared in the Declarations section of a standard module g

The Basic LNC Database Object Tags

Object Tag
Class module cls
Form frm
Form (dialog) fdlg
Form (menu) fmnu
Form (message) fmsg
Form (subform) fsub
Macro mcr
Module bas
Module mod
Query (any type) qry
Query (append) qapp
Query (crosstab) qxtb
Query (data definition) qddl
Query (delete) qdel
Query (form filter) qflt
Query (lookup) qlkp
Query (make-table) qmak
Query (select) qry (or qsel)
Query (SQL pass-through) qspt
Query (union) quni
Query (update) qupd
Report rpt
Report (subreport) rsub
Table tbl
Middle Table trel
Table (attached dBASE) tdbf
Table (attached Excel) txls
Table (attached FoxPro) tfox
Table (attached Lotus) twks
Table (attached ODBC) todb
Table (attached Paradox) tpdx
Table (attached SQL Server) tsql
Table (attached text) ttxt
Table (lookup) tlkp
Pages pge

The LNC Table Field Tags

Object Tag
Autonumber (random non-sequential) idn
Autonumber (replication ID) idr
Autonumber (sequential) ids
Binary bin
Byte byt
Currency cur
Date/Time dtm
Double dbl
Hyperlink hlk
Integer int
Long lng
Memo mem
OLE ole
Single sng
Text (character) chr
Yes/No (Boolean) ysn

The LNC Tags for VBA Variables

Object Tag
Boolean bln
CommandBar cbr
Control (generic; useful when cycling through controls on a form or report) ctl
Currency cur
Database dbs
Double dbl
Form frm
Integer int
Long lng
QueryDef qdf
Report rpt
Single sng
Snapshot snp
String str
Table tbl
Type (user-defined) typ
Variant var

The LNC Tags for Form and Report Controls

(may also be used in code referencing controls)
Object Tag
Attachment att
Bound object frame frb
Chart (graph) cht
Check box chk
Combo box cbo
Command button cmd
Custom control ocx
Frame fra
Hyperlink hlk
Image img
Label lbl
Line lin
List box lst
Option button (Radio Button) opt
Option group grp
Page (on a Tab control) pge
Page break brk
Rectangle (shape) shp
Subform/report sub
Tab control tab
Text box txt
Toggle button tgl
Button btn
Unbound object frame fru

Some Typical LNC Names for Database Objects, Controls and Variables

Object/variable name LNC naming elements Description
tblEmployees tag + base name A table of employee data
qupdSales tag + base name A query that updates sales data
fsubDayMax tag + base name + qualifier A subform that shows the maximum day
intLines tag + base name An Integer variable to hold a value representing the number of lines in a Word table
curSales tag + base name A Currency variable holding a Sales value
pstrForm prefix + tag + base name A public String variable holding a form name
zztblContacts prefix + tag + base name A backup Contacts table, for copying and filling with imported data

References

Part of this article is based on Helen Feddema's book, Expert One-on-One Microsoft Access Application Development, Wiley, ISBN:0-7645-5904-4.

  1. ↑ "Naming Conventions for Microsoft Access (Archived Microsoft Access Content)". http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/dnaraccess/html/msdn_20naming.asp. [yes|permanent dead link|dead link}}]

External links



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