ADO Connection ConnectionString of a Connection
Formating Rules of ConnectionString
Microsoft JET OLE DB Provider on 64 bit systems
Microsoft OLE DB Provider on
both 32/64 bit systems Downloads of Microsoft Data Access Components
ADO Connection
In ASP, the connection of an application to a database or a data file is bridged
by the ActiveX Data Objects Component (ADO) throught utilizing a provider to do
the job. When creating a connection instance to a data source, parameter
"ConnectionString" is used to specify the string value of the connection
information.
ConnectionString of a Connection
The parameter "ConnectionString" is also defined as the property of a connection
object which can be used to set and return the value of ConnectionString. The
optional parameter "ConnectionString" is a series of argument = value statements
separated by semicolons. Although ADO only supports five types of arguments, any
other arguments will also be passed to the provider directly by the ADO without
carrying out any process. The five valid arguments of parameter
"ConnectionString" or the "ConnectionString Property" can be
Argument
Description
Provider=
To specify the name of a provider to use for the connection
File Name=
To specify the name of a provider-specific file, e.g. a persisted data source
object, containing preset connection information.
Remote Provider=
To specify the name of a provider to use for the connection when opening a
client-side connection for Remote Data Service only.
Remote Server=
To specify the path name of the server to use for the connection when opening a
client-side connection for Remote Data Service only.
URL=
To specify an absolute URL as the connection string to identify a resource, such
as a file or directory, for the connection.e
All blank characters, except those placed within a value or within quotation
marks, are ignored
Blank characters will though affect connection pooling mechanism, pooled
connections must have the exact same connection string
If a semicolon (;) is part of a value it must be delimited by quotation marks
(")
Use a single-quote (') if the value begins with a double-quote (")
Conversely, use the double quote (") if the value begins with a single quote (')
No escape sequences are supported
The value type is not relevant
Names are case iNsEnSiTiVe
If a KEYWORD=VALUE pair occurs more than once in the connection string, the
value associated with the last occurrence is used
However, if the provider keyword occurs multiple times in the string, the first
occurrence is used.
If a keyword contains an equal sign (=), it must be preceded by an additional
equal sign to indicate that it is part of the keyword.
If a value has preceding or trailing spaces it must be enclosed in single- or
double quotes, ie Keyword=" value ", else the spaces are removed.
Microsoft JET OLE DB Provider on 64 bit systems
The Microsoft OLE DB Provider for JET and the JET ODBC driver are available in
32-bit versions only. Althogh web pages can be run on 32/64 bit systems, an
application with JET driver can't be run on 64 bit systems because there is no
corresponding JET driver on 64 bit systems.
Ways to resolve the problems are
Run the application using JET driver (in 32-bit only) in WoW64 subsystem to emulate 32-bit
mode on 64 bit systems.
Configure the
web sites application pool of IIS (e.g. IIS 7) to run application in 32-bit mode.
Change the driver of Microsoft OLE DB Provider of the application from JET driver to ACE driver, which are available in both 32-bit and 64-bit
versions. The suggested solution is to use the drivers of SQL Server Express
Edition as a general replacement for JET driver.
Microsoft OLE DB Provider on
both 32/64 bit systems
The
Microsoft JET OLEDB Provider with only 32-bit driver is depricated by the
Microsoft ACE OLEDB Providers with both 32-bit and 64-bit drivers.