The connection panel
This
panel is what you see once you've launched the Diff and going to start
a comparison. Mostly, it consists of two identical panes,
containing the usual SQL Server connection parameters. Some
of the parameters are obvious, but some deserve a comment.
The "Secondary
database" selection at the bottom has 3 states:
- "On the same
server" means that all server-selection fields in the
right-hand connection pane are disabled, so you only need to configure
one set of connection parameters and choose two different databases on
that server;
- "On a separate
server" enables separate server selection in each of the
panes;
- "Start with
one database" completely turns off the right-hand
connection pane, so you only specify one database and the Diff starts
in "exploring" mode. In this mode there is no comparison, but you can
quickly view the schema and script any parts of it.
Note that the [Compare] button remains disabled until you
enter all required connection parameters and specify two different
databases
(except that for "Start with one DB" mode you obviously only need to
choose one). The Diff won't compare a database against itself.
The server
selection combobox is pre-filled with known server names
fetched from several places:
- From the list of 'preferred servers' which Microsoft tools
keep in the registry at "HKCU\Software\Microsoft\Microsoft
SQL Server\80\Tools\Client\PrefServers";
- From the list of server aliases you can define in the MS
Client Network Utility;
- And from the list of recent server names which the Diff
keeps in its own settings.
Note that some of these sources can keep not only a server
name itself, but some additional information like the network library
required or the port number. The Diff implements that by
keeping a piece of connection string associated with each server name
in
the combobox. Therefore when you select a server in the
combobox, some other connection parameters may change accordingly.
The Diff doesn't actually look for available SQL
servers until you tell it to. There is a button next
to the server selection combobox invoking the Server scan
dialog
dialog, which tries to locate all available SQL servers on the LAN.
This dialog is described in
more details here. The results of the server scan may be
either added to the server combo box or one of the servers may be
selected immediately.
The NetLib
field: you can usually leave the default value there. If you
do select a specific net library, you must make sure the
server name is suitable for it. For example, the usual
"Server\Instance" syntax is not valid with the TCP/IP netlib, instead
the server name must contain the server IP or name only, whereas the
port number determines the server instance.
Note that there are two separate timeout
fields: the connect
timeout determines how long the Diff will wait when a
server connection is being established, whereas the query
timeout
specifies how long to wait for a SQL query to return. The default value
of 0 means
the ADO default timeout will be used (which is normally about
30sec). To have longer timeouts, you must explicitly specify
them, in seconds. The timeout parameters apply to all situations when
the Diff accesses the databases:
- Scanning database schemas;
- Executing generated SQL;
- Running data comparisons.
Persistence
To make using the Diff easier for you, the Diff remembers what
you've
entered into the connection panel before:
- The list of servers in the server selection
combobox;
- The full set of connection parameters of the last
comparison you ran.
Besides, you can save any comparison into a file. That saves not only the connection
parameters but also a number of other settings.
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