In my previous article (Intro to DMO), I
described how to use DMO to connect to SQL Server and do some basic tasks, such
as performing a backup. This article will introduce some additional methods
that are very useful when automating administrative tasks. All code has been
tested on SQL 2000, but should work fine with SQL 7.
ExecuteImmediate Method
The ExecuteImmediate gives
you the ability to execute T-SQL or stored procedures from within your DMO
script. If you use ExecuteImmediate as a method of a database object, you get
the same effect as if you had executed a “Use Database” in QueryAnalyzer. You
can also use ExecuteImmediate as a method of the server object, in which case the
database is always the master. Assuming you’ve already
established a connection to your server, this sample code will update
statistics on all objects in all databases.
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Dim oServer Dim oDatabase Set oServer = oServer.LoginSecure = True oServer.Connect "(local)" For Each oDatabase In oServer.Databases ‘2=SQLDMOExec_ContinueOnError oDatabase.ExecuteImmediate "sp_updatestats", 2 Next ‘clean up oServer.DisConnect Set oServer = Nothing |
ExecuteWithResults Method and the QueryResults
Object
ExecuteWithResults works
just like the ExecuteImmediate method, except you have to assign the results of
the method to a QueryResults object. The QueryResults is my least favorite
object. Instead of returning an ADO recordset, or at least a true object that
would support for/each interation, it is essentially an array. To make matters
worse, you have to use different methods to retrieve column values depending on
the column datatype. Still, it is good enough for most admin tasks and allows
you to work solely within DMO without having to have any knowledge of other
object models.
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Dim oServer Dim oDatabase Dim oResults Dim lCount Dim sMessage Dim SQL Dim J Set oServer = oServer.LoginSecure = True oServer.Connect "(local)" SQL = "Select Name from SysUsers where For Each oDatabase In oServer.Databases
Set
sMessage
For J = 1
sMessage
Next
sMessage
Set
MsgBox Next ‘clean up oServer.DisConnect Set oServer = Nothing |
Script Method
Think of the scripting
options available in Enterprise Manager. You can reproduce them all in DMO,
plus some! In this example I’m creating one script per database containing all
of it’s views. I’m using the appendtofile flag so that each time I script an
object, it doesn’t overwrite the previous script. The primaryobject flag is the
one that tells DMO to generate the DDL for the object.
This example also makes use
of the CommandShellImmediate method – which directly corresponds to xp_cmdshell.
Take a look also at the nested loops, the outer one for the databases, the
inner for the views – objects make this kind of looping incredibly easy.
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Dim oServer Dim oDatabase Dim oView Set oServer = oServer.LoginSecure = True oServer.Connect "(local)" ‘this deletes previous versions of scripts – use oServer.CommandShellImmediate "Delete ‘loop through each view in each database, creating ‘to create all of the views For Each oDatabase In oServer.Databases For Each
‘SQLDMOScript_AppendToFile=8192
‘SQLDMOScript_ObjectPermissions=2
‘SQLDMOScript_ToFileOnly=64
‘SQLDMOScript_PrimaryObject=4
oView.Script 8192 + 2 + 64 + 4, "C:DMO_Views_" & Next Next ‘clean up oServer.DisConnect Set oServer = Nothing Msgbox "Done." |
ListAvailableSQLServers
Method
This method returns a
NameList object – a collection object in which the members are not strongly
typed. In order to iterate the collection using the for/each syntax, you can
use a variable of type variant for the member object. In this example I’m
showing how you can retrieve the number of databases for each SQL Server that
is visible on the network.
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Dim oApp Dim oServer Dim oDatabase Dim oNames Dim oName Set oApp = Set oNames = oApp.ListAvailableSQLServers() For Each oName In oNames
Set
oServer.LoginSecure = True
oServer.Connect oName
MsgBox
oServer.DisConnect
Set Next ‘clean up oApp.Quit Set oApp = Nothing |
Wrap Up
Remember, you can use DMO
from any COM compliant language. Swynk reader Gregg Murray writes:
"You can create great administrative web pages that
tell you lots of info about a multitude of jobs, servers, disk space warnings,
etc… All on one freeform ASP page. This gives you the ability to create
really friendly "dashboards" that can help you perform common
administrative tasks from a web page! Ideal alternative to Enterprise
manager, especially when you need to administer your SQL servers over a 28.8
modem connection on RAS!"
Excellent point! I haven’t
yet used DMO with ASP, but as soon as I read that I thought of a project at
work that would be perfect for using the two together – I’ll let you know how
it goes in a future article.
