Using New Data Types in 2008 Andrew Couch UK Access User Group ASC associates

Flow of Presentation Data types and products Share Point : Access & SQL Server SQL Server : Access & Visual Studio SQL Server New Data Types Updating Data & Multi-user Issues Summary

Why are we interested in Data Types? What we do with data  Exchange Converting and exchanging data between products  Applications that present data Linking applications to back-end data sources  Applications that maintain data updating data with applications linked to back-end data source

Which Products will we consider? Products  Access Application and data source  SQL Server data source and application components, also report services  Share Point Application and data source (SQL Server)  Visual Studio Application

What Data Types do the Products support? Access (2007) GUID Multi-value fields Share Point (2003) see next slide SQL Server (2008) Visual Studio (2005/8) n prefix for Unicode

Share Point (2003)

Share Point under the hood Data is held in the AllUserData table which has a generic set of fields, nvarchar1,nvarchar Text1,Text

Access to Share Point Data Types; MOSS

Access (2007) & Share Point Attachments (share point lists) Multi-value fields (share point lists)

Share Point a Data/Object Model; WSS us/library/ms aspx us/library/ms aspx

Access to SQL Server Data Type Mappings Yes/No (boolean) : bit  Access True -1, SQL Server True 1; also SQL Server boolean is tri-state 0, 1 and NULL Text : varchar or nvarchar or char or nchar Date/Time : datetime Currency : money Autonumber : int (identity property) OLE Object : image, varbinary, filestream Memo : text or varchar(max) Number : various mappings

Access Yes/No Data

Yes/No (without a default) Translated To SQL Server

Access Memo and OLE Data Types

Access Using SQL Server IMAGE and TEXT Data Types

Visual Studio Editing Records in DetailsView; issues with Text Data Type

Visual Studio and Image/OLE Data issues with Image Data Type

Access & SQL server Varchar(max) and Varbinary(max)

Visual Studio DetailsView now works for Updates when using Varchar(max)

Visual Studio, Images and OLE still a problem with Varbinary(max) some people would suggest that image data should not directly held in the database and instead a text link is used to point to an external image file which works around this issue

Mini-summary Access to SQL Server  MEMO to VARCHAR(max) or TEXT, probably TEXT safer bet but VARCHAR(max) more flexible  OLE to IMAGE or VARBINARY(max), FILESTREAM ? Visual Studio  VARCHAR(max) a better choice  OLE/IMAGE data doesn’t work for bound controls

SQL Server (2005) XML data type  office requires program code using new SQL Native Client drivers to manipulate this varchar(max), nvarchar(max)  advantages for programmers as can use as a variable (not possible with older text data type) varbinary(max)

Date & Time Data IBM DB2  DATE, TIME and TIMESTAMP date range to Oracle  DATE (includes time), TIMESTAMP, date range January BC to SQL Server (2000/2005)  DATETIME, SMALLDATETIME, date range to for DATETIME, when no date given defaults to 1st January 1900 Access – DATE/TIME  date range to ,when no date given defaults to 30th December 1899 and hides date SQL Server (2008)  DATE, TIME,DATETIME2, DATETIMEOFFSET range :00:00: to :59:59:

Access allowing Updates to new Date and Time Data Types

Searching some limitations where fields are strings

Controlling Time Precision

SQL Server (2008) Filestream  Unstructured large object data DATE and TIME  Dates from 01/01/0001 to 31/12/9999  Times accurate to 00:00:00: DATETIME2 and DATEOFFSET  New combined date and time data types with higher accuracy, Combines above, offset type includes time-zone data HIERARCHYID  Optimised for data hierarchies (special functions) GEORGRAPHY and GEOMETRY .NET-based spatial data  First deals with round-earth co-ordinates, second uses a flat-earth style of co-ordinates  Special functions

Geography It comes as no surprise that this renders in a binary type format and you can’t edit it Stored procedures and pass through queries to the rescue!

With a little Magic

Geography Methods

Timestamps & Multiple Users SQL Server Overwrite data when changed Optimistic row versioning Timestamp checking Visual Studio does not utilise timestamps on bound controls the new LINQ will support timestamp concurrency

Access Row Versioning & Timestamps Row Versioning SQLExecDirect: UPDATE "dbo"."authors" SET "au_fname"=? WHERE "au_id" = ? AND "au_lname" = ? AND "au_fname" = ? AND "phone" = ? AND "address" = ? AND "city" = ? AND "state" = ? AND "zip" = ? AND "contract" = ? Timestamps SQLExecDirect: UPDATE "dbo"."authors" SET "au_fname"=? WHERE "au_id" = ? AND "ts" = ? Timestamps improve efficiency and remove potential problems with rounding errors in numerical data

Example Visual Studio Update handling Null Values UpdateCommand = "UPDATE [Customers] SET [CustomerID] [CompanyName] [ContactName] [ContactTitle] [Address] [City] [Region] [PostalCode] [Country] [Phone] [Fax] WHERE [CustomerID] AND [CompanyName] AND COALESCE([ContactName],'') = AND COALESCE([ContactTitle],'') = AND COALESCE([Address],'') = AND COALESCE([City],'') = AND COALESCE([Region],'') = AND COALESCE([PostalCode],'') = AND COALESCE([Country],'') = AND COALESCE([Phone],'') = AND COALESCE([Fax],'') =

Summary We have a diverse set of data types in the different products Need to test data types for product compatibility, don’t forget different versions and drivers can have an impact Access and Share Point very good compatibility Access and SQL Server good compatibility Share Point data easily exported and linked MOSS but WSS more difficult Please, Please can I have a nice tree presentation for XML data, then I may be tempted to use it!!!!!! SQL Server 2008 new data types hold great promise, and it will possible to do a lot with then in Office 2007

ASC Associates Software consultancy specialising in Access, SQL Server and.net applications Migration Upsizing SQL Tool  MUST upsizes Access databases to SQL Server  MUST+SQL converts Access queries to views and stored procedures  MUST+Web converts Access forms to web forms in Visual Studio projects