The View - Leveraging Lotuscript for Database Connectivity

Leveraging
LotusScript for
Database
Connectivity

Bill Buchan
HADSL
© 2007 Wellesley Information Services. All rights reserved.

Why Are We Here?
• What is the target audience?
 Lotus Notes developers who use server-based agents
• What is this talk about?
 Lotus Notes is often perceived as a data “silo” …
 Difficult to get data into
 And difficult to get data out of
 … this is not the case
 This presentation explores a multitude of ways of interfacing
Notes databases with enterprise relational databases

2

Who Am I?
• Bill Buchan
• Dual Principal Certified Lotus Professional (PCLP) in v3,
v4, v5, v6, v7
• 10+ years senior development for Enterprise customers
 Learn from my pain!
• 5+ years code auditing
• CEO of HADSL
 Developing best-practice tools

3

What We’ll Cover …
• Overview
• LSX
• LS:DO
• DCR
• Wrap-up

4

Overview
• This session:
 Is mostly about code
 Lots of take-home code examples
 Is a deep-dive in terms of theory

5

Connections: Overview
• “Lotus Notes cannot share its data with other
databases”
 Absolutely not
 Support for this dates back over 10 years!
• Multiple methods
 This presentation leads you through some of the more
popular ones
 Highlights the pros and cons of each

6

Connections: Overview (cont.)
LSX LS:DO DCR JNDI/XML
Performance High Low Med High
ODBC Connection Required No Yes Yes No
Native Client Required Yes No No Yes
Platform Independent Yes Yes Yes Yes
LotusScript Only Yes Yes Yes No
Supported Yes No Yes Yes
Runs on Client Yes Yes Yes Yes
Runs on Server Yes Yes No Yes

7

Tips: General
• In all of these examples, I shall hard-code user names
and passwords for simplicity
 This is NOT a good production best practice!
 Use encryption keys, profile documents, etc., to soft-code
these in production
• Any attempt by LotusScript to access data outside the
current database may result in error
 Error handling is therefore mandatory
 Logging of scheduled agents is mandatory

8

• Overview
• LSX
• LS:DO
• DCR
• Wrap-up

9

Overview: LSX
• LotusScript-based
 Such a small learning curve
• Relies on native client support
 So you have to install your database client and/or drivers
• Is fast
 This doesn’t have to use ODBC
 But ODBC is used for MS SQL and Access
 Remember, ODBC v2 doesn’t like Unicode
 This technology is used in the Lotus Enterprise Integrator
 Formerly “Notespump”
 Good for bulk transfer-style applications

10

Methodology
• We shall attempt to:
 Test this against a local Access database using ODBC
 Test this against an Oracle database
• Our data looks like:

• And for Access, we need an ODBC connection

11

Demo: Read Table to Log
• Let’s get a feel for what we are doing
• In this demonstration, we will:
 Connect, using ODBC, to an Access database
 Collect all records in a CUSTOMERS table
 Pull ALL fields from all records
 Write all this information to a Notes log

12

Demo

Demo

Read Table to Log

13

Architecture Design Goals
• When we write LSX applications, we should:
 Write as little code as possible
 Create comprehensive error handling
 Create logs of both success and failure
 Try not to hard-code the database structure
 Try and reuse and componentize
 After all, we might change databases later!
 Ensure that our top-level logic is:
 Focused on the business rules for data transfer
 Is maintainable
 After all, this will change!

14

Architecture Design Overview
• In order to access data, we must:
 Connect to the database provider
 And then connect to the data itself

• Object-oriented LotusScript lends itself to this model
 We shall create a:
 baseClass: This handles logging
 baseConnectionClass: This handles the connection to the
data source
 baseConnection<DB>Class: These are database-specific
classes
 Operation classes
 These should NOT be database specific

15

Architecture Design Results
• This means that we separate:
 Logging
 Basic connection
 Operation
• Thus, reusing lots of code
• All database-specific code is held in a single library
 Can be easily “swapped” for another
 Platform and database differences can exist during our
operations
 Test on the platform, version, and database that you will
implement on

16

Class Inheritance and Code Use

Logic for Connection BaseClass Logging, Error Handling
Code

BaseConnectionClass

ReadTableClass

BaseConnectionODBCClass
Operations Class

BaseConnectionOracleClass ODBC-Specific Code

Oracle-Specific Code Example agent uses a
specific database
connection and one or
more helper function
classes

Agent

17

Connecting to Oracle
• Now, let’s try connecting to Oracle
 We need to:
 Install the Oracle client
 Connect it to the Oracle database server

18

Some Oracle Tips
• Setting up an Oracle server is not trivial
 Oracle is an enterprise-strength database system
 As big, complex, and difficult as a dozen mother-in-laws
 So give yourself time!
• Some tips:
 The Connection string in Oracle looks like:
 CUSTOMERS_oracle02.marykirk.local
 This is:
 The name of the application — in our case “Customers”
 And then the network host address
 Either as a Domain Name System (DNS) host address
or as an Internet Protocol (IP) address

19

More Oracle Tips
• Try to use some Oracle tools to validate that you have:
 A proper connection
 Sufficient access to the application
 Sufficient access to the tables
• Remember, you can use DCR to validate connections

20

Network Architecture
• If you run Lotus Connector (LC) LSX code on the server:
 The server must have:
 A connection to Oracle
 The Oracle Client software drivers

• If you run LC LSX code on the Notes client:
 The client must have:
 A connection to Oracle
 The Oracle Client software

• Installing Oracle Client on all workstations is not trivial!
 Consider using LC LSX on the servers only

21

The Base Class
• Our base class Class baseClass

contains all ‘ returns true if this class is valid
“Infrastructure” Public Property Get Valid As Boolean

support, such as: ‘ Our constructor. Sets up logging
 Logging Sub new()

 Error trapping ‘ Class destructor ensures proper closure of Log
Sub delete()

‘ Log a message
Public Function logEvent(msg As String) As Integer

‘ Handle run-time errors
Private Function raiseError() As String
End Class

22

Class baseConnectorClass
' This class extends our BaseClass and adds the capability to open and close a connection
' Note that this is never used directly – and is overridden by our database-specific classes.
‘ This provides the business logic framework for our database specific connection classes
Class baseConnectorClass As BaseClass

‘ Expose some properties
Private Function getServer As String
Private Function getUserName As String
Private Function getPassword As String
Private Function getTable As String
Public Function getSession As LCSession
Public Function getConnection As LCConnection

' The base constructor for this class. Note that it doesnt actually
' do any connection work - it just sets up the base variables
Sub new(srv As String, un As String, pw As String, tb As String), baseClass()

‘ And the destructor. This ensures that the connection object is closed
Sub delete()
End Class

23

Class baseODBCConnectorClass
• All of our business logic is held in baseConnectorClass
 We need to put the database-specific code in only this class
 In this case, it is all implemented in the constructor
• If we change the business logic later on:
 We have to change only baseConnectorClass

' This class extends our BaseConnectorClass and adds the
‘ capabilty to open and close an ODBC Connection
Class baseODBCConnectorClass As BaseConnectorClass

‘ Supply a new constructor for this class
Sub new(srv As String, un As String, pw As String, tb As String)
End sub

24

Insulating Database Connections from Business Logic
• One main goal is to insulate our database-specific
connection information from our business logic
 It makes it easier to switch databases in the future, if
necessary
• In this database, I hold all database-specific information
in a profile document
Set docProfile = dbThis.GetProfileDocument("Profile")

Dim Connection As Variant

Select Case docProfile.Database(0)
Case "ODBC"
Set connection = New baseODBCConnectorClass _
(docProfile.System(0), "", "", "")
Case "Oracle"
Set connection = New baseOracleConnectorClass _
(docProfile.System(0), docProfile.UserName(0), docProfile.Password(0), docProfile.MetaData(0))
End Select
25

Class fieldClass
• fieldClass Class FieldClass

 Helps us define which ‘ Our two members – a name and a field
fields we want returned Public FieldName As String
from our data object Public Field As LCField

 Used to extract data ‘ get the value of this field
Property Get Value As Variant

‘ Construct this field class
Sub new(fName As String, F As LCField)

End Class

26

Class baseODBCConnectorClass — Constructor
• This pseudo-code Set Me.lc_Session = New LCSession()

shows the steps If ( Me.lc_Session.Status <> LCSUCCESS ) Then

towards connecting ‘ Bale out of the function…

to our LC LSX ‘ Check to see that the odbc2 LSX Support is available.
If (lc_Session.LookupConnector ("odbc2")) Then
target data server …

• Differences from an ‘ Now set up our Connection

ODBC connection Set me.lc_Connection = New LCConnection ( "odbc2" )

 The connection token ‘ Set up our data source name
Me.lc_Connection.Server = Me.getServer()
is “oracle8”
 The username and ‘ And finally connect
Me.lc_Connection.Connect
password are
specified ‘ Check to see that the connection has worked
If (Me.lc_Connection.isConnected = False) Then
…

27

ReadTableClass
• ReadTableClass Class ReadTableClass As baseClass

 Allows us to read the result ‘ Our constructor. Pass in our
of an SQL Query ‘ database connection object
Sub new(newConn As Variant)
 Returns each table row as a
LIST of FieldClass items ' set up our read operation
‘ by passing in an SQL statemement
Public Function getRecords( _
strSelection As String) As Long

‘ Call this till it returns false, return
‘ each row of the table as a list
‘ of resulting fields
Public Function getNextRecord( _
index As Long, returnedFields _
List As FieldClass) As Integer

End Class

28

Using ReadTableClass
• Our controlling code ‘ set up our database connection
Set connection = New _
 Set up a database baseODBCConnectorClass( _
connection “CUSTOMERS”, "", "", "")

 Create a ReadTableClass ‘ set up our ReadTableClass object
Dim rc As New ReadTableClass(connection)
object
‘ Check to see its valid
 Check to see whether If Not rc.Valid Then
it’s valid …

‘ Do our SQL thing
 Run some SQL If (rc.getRecords( _
"SELECT * from CUSTOMERS")) Then

 Process the results While rc.getNextRecord(index, returnedValues)
…

29

Processing the Results from ReadTableClass
• It’s a case of: ------------------ New Record retrieved ----------
ID 1
 Retrieving each ROW of data Name Lotus
Contact Mike R.hodin
 Iterating through the LIST of Address Lotus House
fieldClass items and City
State
Westford
MA
processing them ZIP 90210
Country USA
• Agent “Read Tables to Log” dateFirstContact 01/01/1990 00:00:00
CreditLimit 5000000.0000
just prints them Employees 1000
…

Forall thisF In returnedValues
Call rc.logEvent(" " + thisF.fieldName + Space(30-Len(thisF.fieldName)) + _
Chr(9) +" [" + Cstr(thisF.Field.DataType) + "]" + Chr(9) + _
Implode(thisF.Field.Text, ", "))
End Forall

30

Demo: Read Table to Documents
• Let’s use the same underlying code:
 Synchronize this information with Notes data
 Use the ID field to match up SQL entries with Notes entries
 For simplicity, we shall just overwrite the Notes data with
the SQL data
 Note we are not requesting specific fields
 We write ALL field information to a Notes database
 We use the same field name in SQL and Notes
 This might not be good in production
 Consider pre-fixing the Notes field names to avoid
name collisions

31

Demo

Demo

Read Table
to Documents

32

Let’s Write to SQL
• In this case, we need to define which fields we shall
update
 This information is used to define:
 The SQL target field
 Which field in Notes we pull data from
 The data type
 This had better match the SQL data type!
 Again, we want the operations class to do all the hard work!

33

insertTablesClass
• Our class allows us to: Class InsertTableClass As baseClass

 Define a series of field ' Our constructor. Pass in the Connector.
names we shall write Sub new(newConn As Variant)

data to ' Call this for each field we wish to append,
 Pass a variant array of ‘ passing in a name and a type
Public Function appendField( _
values (in the same order fieldName As String, fieldType As Long) _
as our fields were As Integer

appended) ' Commit to inserting these records.
• This is still pretty hard ' This returns the number of records successfully
‘ inserted, NOT true or false.
work Public Function insertRecord( _
values() As Variant) As Integer
 We have to track all
fields, etc. End Class

34

insertFieldClass
• insertFieldClass Class insertFieldClass
‘ Our constructor. Pass in our InsertTableClass
 Helps define the Sub new(newIT As Variant)

fields, field types, ‘ Append a field name and an LSX field type
and values to Public Function appendField( _
transfer from the strName As String, Ltype As Long) As Integer

Notes document to ‘ Call this once you have set all your field names
the SQL table Public Function setUpFields() As Integer

 For simplicity, in this ' Using our fieldList, save the field values
code instance we are ‘ from this document to to our InsertTableClass
Public Function saveFieldsFromDocument( _
assuming that the doc As NotesDocument) As Integer
field names are
identical in Notes End Class

and SQL

35

insertTableClass and insertFieldClass Usage
• Define a new ‘ Create a new InsertTable Class
InsertTableClass Dim it As New InsertTableClass(Connection)

‘ And create a InsertFieldClass, associating
• Define a new ‘ it with our table Class.
InsertFieldClass Dim ic As New InsertFieldClass(IT)

‘ Define the fields
Call ic.appendField("ID", LCTYPE_NUMERIC)
• Define our fields Call ic.appendField("Name", LCTYPE_TEXT)
…

‘ And “freeze” it there.
Call ic. setUpFields()
• Freeze the definition
‘ And for one or more Documents, push the
‘ Data across.
• Push the data Call ic.saveFieldsFromDocument(doc)

36

Demo

Demo

Insert Rows
into SQL

37

Performance
• Creating LCField items is expensive
 We define our LCFields before inserting data
 Instead of creating new LCField items within the loop for
each iteration, we create them ONCE outside the loop and
reuse them
 Adds slightly to the complexity
 Hence the requirement for insertFieldsClass

38

• Overview
• LSX
• LS:DO
• DCR
• Wrap-up

39

Introducing LotusScript Data Object (LS:DO)
• LS:DO was the first data interface
 And is reportedly no longer supported
 You may find some code that still relies on this
• LS:DO uses ODBC v2 drivers to access data
 You cannot access Unicode data
 This was introduced in ODBC v3.5
 The client must have an ODBC definition for the target data
source on his machine, if you are running client-based code
• Let’s dive straight into a demo …

40

Demo

Demo

Read Table
Definition

41

Using LS:DO
• Create a new connection Const SQL_TABLE = "CUSTOMERS"
Const SQL_QUERY =
"SELECT * FROM CUSTOMERS"

• Create a query and link it to our Set Connection = New ODBCConnection
connection Connection.ConnectTo(SQL_TABLE)

If Not Connection.IsConnected Then
• Create a result set and connect it …

to our query Dim Query As New ODBCQuery
Set Query.Connection = Connection

• Set the SQL query Dim Result As New ODBCResultSet
Set Result.Query = Query

• Execute the query Query.SQL = SQL_QUERY

Result.Execute

42

LS:DO Result Set Processing
• The ODBCResultSet Object now contains all the results
 You can extract field information
 You can extract actual values
 This code extracts field name and size information
If Not Result.IsResultSetAvailable Then
Messagebox "I failed to get results from SQL Query: “ + _
SQL_QUERY, 48, "Failed to get Results"
Exit Sub
End If

Dim fields List As String
Dim i As Integer
For i = 1 To Result.NumColumns
Print "Field: " + padString( result.FieldName(i), 30) + _
"Size: " + padString(Cstr(Result.FieldSize(i)), 5)

fields(result.FieldName(i)) = result.FieldName(i)
Next

43

LS:DO Result Set Processing (cont.)
• To extract the result rows themselves, use:
 Result.getNextRow ID
Name
1
Lotus

 Result.IsEndOfData Contact
Address
Mike R.hodin
Lotus House
City Westford
State MA
ZIP 90210
Country USA
dateFirstContact 01/01/1990
CreditLimit 5000000
Employees 1000

While Not result.IsEndOfData
Forall thisField In fields
Print " " & padString( "" + thisField, 30 ) & Chr(9) & Result.GetValue(thisField)
End Forall

Call Result.NextRow()
Wend

44

LS:DO Tips
• LS:DO supports transaction processing
 You could — if your SQL data source allowed — switch on
Transaction mode
 odbcConnection.IsSupported(DB_SUPP_TRANSACTIONS)
 You could then perform multiple updates
 Commit them all at once
 odbcConnection.CommitTransactions

45

LS:DO Summary
• LS:DO was a fairly simple, robust ODBC connection
 You might have some code that relies on it
• I would advise you to:
 Identify any code that relies on LS:DO
 Refactor that code to use LSX

46

• Overview
• LSX
• LS:DO
• DCR
• Wrap-up

47

Introducing DCR
• Data Connection Resources (DCR)
 New in Domino 6
 Allows you to perform real-time, user-based SQL database
access
 Very useful for front-end applications
• However:
 It requires constant access to the target database
 It requires Domino Enterprise Connection Services (DECS)
 Running on the server on which your application is hosted
 It pools all SQL database access via the DECS server

48

Create a New Shared Resource — Data Connection
• Set a name and alias
• Set the data connection type
• Enter username and password, if required
• Choose the data source
• And choose the object
• Use Browse metadata
to validate the connection

49

Link the Data Source to Your Form
• On the Form Properties — advanced tab, click Browse
 Choose the data connection and the metadata object

50

Link the Fields to the Data
• On the field properties:
 Check “External data source”
 At the bottom, use the Browse
button to select the data source,
metadata
• One field needs to be defined as
the key field
• Remember to check “Store data
locally” if you want to see this
data on views!

51

DCR: What Would I Use It For?
• Very useful for:
 Applications that are permanently connected
 Applications that require instant lookup of external data
• You could use Notes information and …
 Perform lookups to populate the document
 Update status information on user request

52

Form Manipulation
• Bear in mind that all this logic is held on the Form
design element
 You could use one Form to populate/refresh data
 And allow users to work another Form
 Which just displays the data on the document

53

Demo: DCR
• In this demo, I will:
 Demonstrate data being updated in Notes and pushed to SQL
 Demonstrate data being updated in SQL and pushed to Notes
 Show you the DCR common element, as well as the Field
definition

54

Demo

Demo

DCR demo

55

• Overview
• LSX
• LS:DO
• DCR
• Wrap-up

56

Resources
• Constantin Florea, Notes and Domino Connectivity: A
Collection of Examples (IBM Redpaper, March 2001).
 www.redbooks.ibm.com/redpapers/pdfs/redp0115.pdf
 Check out the abstract here:
 www.redbooks.ibm.com/abstracts/redp0115.html?Open

• Brian Benz and Rocky Oliver, Lotus Notes and Domino 6
Programming Bible (Wiley, 2003).
 www.amazon.com/gp/product/0764526111

57

Resources (cont.)
• Object-Oriented LotusScript:
 www.hadsl.com/hadsl.nsf/Documents/Object+Orientated
+Programming+in+LotusScript+(The+View)!OpenDocument
• The Notes FAQ!
 www.keysolutions.com/NotesFAQ/
• Notes.Net (of course)
 www.notes.net

58

7 Key Points to Take Home
• Domino can easily interact with other data sources
• LS:DO, whilst powerful and easy to use – is no longer
supported
 Consider refactoring this
• LSX performs bulk updates between Domino and other
data sources
 Simple, fast, efficient
• DCR allows real-time update in user context
 And centralizes data lookup via the server

59

7 Key Points to Take Home (cont.)
• Consider that the target data source will change
• Logging and error trapping
 Mandatory
 Ensure that you know of issues before your users
 Monitor this interface
• This interface code will change often
 Write for maintainability!

60

Your Turn!

How to contact me:
Bill Buchan
Bill@hadsl.com
61

The View - Leveraging Lotuscript for Database Connectivity

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