AdsClass++
Working with the
Advantage Database Server
AdsClass++ is a object oriented binding of the
ADS DBMS to a Xbase++ application. The
communication is based on the ADS API and does
not use the Alaska ADSDBE. All tables or SQL
queries are kept in objects.
Advantages of AdsClass++:
fast because based on the ADS API
supports all ADS versions, also the local engine
supports all ADS table formats:
DBF, CDX, VFP, ADT
supports all data types
supports Rawkey indexes
supports all further ADS functionalities
simplest integration of SQL
thread save or thread spanning useable
access solely via objects without workarea
Developer Version with sourcecode
English and German documentation
and samples
The base idea behind this library is the encapsulation
of a data table into an object. Xbase++ can define
dynamic classes and can create the belonging objects at
runtime.
The table structure is build in as ACCESS ASSIGN
methods. For the navigation, search, filter, scope,
etc. methods are available. Every Xbase++ file
command is replaced by a conform method.
Additional the Xbase++ commands are enhanced
with productive methods.
A further advantage of the objects is the typecast.
They can be deployed like all other variables,
passed as parameters and evaluated, etc.
Solely the table object communicates with the ADS,
whereby no workarea is used. Hence this class is
more useful for new developments less for converting
old Clipper code.
Our experience with table objects shows that the
code is easier readable, better to maintain
and less prone to error regarding to table access.
Especially with MDI applications the
connection of a table to a dialog is relieved.
This concept is realized in XClass++ for all Xbase++
DBEs and arrays. AdsClass++ integrates
itself seamless into XClass++, but can
also be deployed independent from XClass++.
Hence the use of table objects encapsulates an
application from the data access technique.
Here the most important components as overview:
dsAceSession, create and maintain a connection to
the ADS server, for further connections to the same or
another ADS server a new object must be created.
adsConnection := dsAceSession():New()
adsConnection:connect("\\myServer")
? adsConnection:IsConnected()
AdsSetDefault("\\myServer\myShare\myDir")
dbTable :=
OpenAceTable("customer",adsConnection )
dbTable:close()
adsConnection:disconnect()
dsAceDD, build connection to an ADS
Datadictionary.
adsDD:=dsAceDD():New()
adsDD:connect("\\myServer\myShare\myDir")
? adsDD:IsConnected()
dbTable := adsDD:OpenTable("Kunde" )
dbTable:gotop()
With that class an ADD is maintained too:
o create groups and users
o administration of transactions
o maintenance of tables, indexes, views, SQ functions
and stored procdures
o opening of application-global useable tables
Transaction
per connection (dsAceSession or dsAceDD)
a transaction can be started.
adsConnection:BeginnTransaction()
beginn sequence
...
adsConnection:CommitTransaction()
recover
adsConnection:
RollBackTransaction()
end sequence
dsAceTable, derivations of that are created table
specific and represent a table. A table can be here a
physical table, a SQL query, a view or the result of a
stored procedure. There is no distinction between
creation or use.
o table opening
dbTable := OpenAceTable("Customer",
adsConnection/adsDD )
dbTable:gotop()
? dbTable:CUSTID // 4711
if dbTable:rlock()
dbTable:CUSTID := 4712
dbTable:unlock()
endif
? dbTable:alias // CUSTOMER_1
? dbTable:tablename() // CUSTOMER
do while !dbTable:eof()
….
dbTable:skip()
enddo
dbTable:cose()
o indexing
// NTX
dbTable:ordcreate("NAME",,;
"upper(lastname)+Upper(firstname)")
// CDX
dbTable:ordcreate(,"NAME",;
"upper(lastname)+Upper(firstname)")
// ADT,fieldtype CiCharacter,Rawkey Index
dbTable:ordcreate(,"NAME",;
"lastname;firstname")
// descend sort
dbTable:ordcreate(,"NAME",;
"lastname;firstname",,ADS_DESCENDING )
// or special collation
dbTable:ordcreate(,"NAME",;
"lastname;fisrtname",,,,;
"GERMAN_VFP_CI_AS_1252" )
Rawkey indexes are binary and can mix all data types
and are therefore extremely performant!
o and the respective search
// NTX, CDX
dbTable:ordsetfocus("NAME")
dbTable:seek(upper(padr("Müller",20))+;
upper(padr("Alfred",20)))
// ADT, Rawkey Index
dbTable:seek({"Müller","Alfred"})
? dbTable:found()
o filter and scope:
// is evaluated at client side
dbTable:setfilter({|db| myFilter(db)})
// is evaluated at server side
dbTable:setfilter(,"customer=‘Smith‘")
// is optimized by index
dbTable:setaof("customer=‘Smith‘")
// top and bottom scope
dbTable:Setscope(, "BERLIN")
SQL (customer can be a table or view)
dbTable := OpenSqlTable(,"select * from”+;
" customer where name like ‘Smith%’”,;
adsConnection )
SQL with parameters
sqlConn :=;
adsSqlTable():New(adsConnection)
sqlConn:Prepare(;
"SELECT * from customer where city=:P1")
sqlConn:SetParam("P1", "Berlin")
dbTable := sqlConn:Execute2Server()
sqlConn:SetParam("P1", "Hamburg")
dbTable := sqlConn:Execute2Server()
sqlConn:Close()
The table object of a SQL result can be indexed too!
SQL stored procedures
If a stored procedure returns a resultset, it is used like
every other table
sqlConn :=;
adsSqlServer():New(adsConnection)
dbTable := sqlConn:SQL2Table(;
"execute procedure sp_MyProc()")
dsAceMg, ADS management for display and
maintenance of ADS settings and parameters
o display of logged users
o display of opened tables
o display of locked records with the belonging users
o disconnecting of users
dsAdsListening, class for handling notifications
received from ADS Server. Notifications which are
announced previously, can be received and handled in
a thread.
// initialize in MAIN
AdsListening(dsAceDD)
// create dialog with browse
dlgWindow := xbpDialog():New(...)
...
//announce events, browse will be refreshed
// automatically, if a record was saved.
AdsListening():CreateEvent(dlgWindow,,;
"ARTICLE.UPDATE ",;
{|| dlgWindow:oBrowse:RefreshAll()})
More informations for ADS under:
www.sybase.com/products/databasemanagement
An trialversion with full functionality, documentation
and samples can be downlaoded from
www.ds-datasoft.de
Contact:
DS-Datasoft GmbH&Co.KG
An der Kirche 5
D-87654 Friesenried
Tel. (++49) 8347 981370
info@ds-datasoft.de
