Editing Leszynski naming convention

{{Refimprove|date=October 2020}}

The '''Leszynski naming convention''' (or '''LNC''') is a variant of [[Hungarian notation]] popularized by consultant Stan Leszynski specifically for use with [[Microsoft Access]] development.<ref>{{cite web|url=http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/dnaraccess/html/msdn_20naming.asp|title=Naming Conventions for Microsoft Access (Archived Microsoft Access Content)|website=MSDN.Microsoft.com}}{{Dead link|date=February 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Although the [[Naming convention (programming)|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 [[Object (computer science)|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.

{| class="wikitable"
|-
!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 ===
{| class="wikitable"
!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===
{| class="wikitable"
!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===
{| class="wikitable"
!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===
{| class="wikitable"
!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===
{| class="wikitable"
!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===
{| class="wikitable"
|+(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===
{| class="wikitable"
!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}}.
{{reflist}}

==External links==
*[http://c85.cemi.rssi.ru/access/Books/A97ExSol/indexc.htm Leszynski Naming Conventions for Microsoft Solution Developers]
*[http://www.helenfeddema.com/Files/code10.zip LNC Renaming Add-in – A free Access add-in that automatically applies the LNC to an Access 2000, 2002 or 2003 database]
*[http://www.xoc.net/standards/rvbanc.asp RVBA Conventions]

[[Category:Source code]]
[[Category:Naming conventions]]