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 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. Most
of the parameters are obvious, but some deserve a comment.
The "Secondary
database" selection at the bottom
has 3 states:
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"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;
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"On a
separate server" enables separate server
selection in each of the panes;
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"Start
with one database" completely turns off
the right-hand connection pane, so you only specify one database
and the Diff starts in the "exploration" mode. In this mode there
is no comparison, but you can quickly view the schema and script
any parts of it.
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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:
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From the
list of 'preferred servers' which Microsoft tools keep in the
registry;
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From the
list of server aliases you can define in the MS Client Network
Utility;
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From the
list of recent server names which the Diff keeps in its own
settings.
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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 any 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:
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Scanning
database schemas;
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Executing
generated SQL;
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Running data
comparisons.
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Persistence
To make using the Diff
easier for you, the Diff remembers what you've entered into the
connection panel before:
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The list
of servers in the server selection combobox;
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The full
set of connection parameters of the last comparison you ran.
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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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