Getting Database Data when using a database, there are two
places where a detailed request for data can be located inside a program that is separate from
the database inside the database itself
a stored procedure is a previously created query or program in a database
SQL Server Stored Procedures precompiled in SQL Server so they run
faster can be reused to avoid recoding make code simpler
like subprocedures do better security
can give users access to data from stored procedures rather than to whole tables
Stored Procedures code to manipulate database (retrieve data,
add, change, delete) stored in database like subroutine, can use in multiple programs
(but not with Access database) less storage: once instead of multiple copies easier to update than multiple copies stored queries run faster inside database makes it easier to migrate applications to
other platforms or scale up to larger volumes
Stored Procedures with VB create or open a Visual Basic project Data>Add new Data Source to get
an existing SQL Server database and select the tables that you will use
View>Server Explorer expand the database you want, right-
click Stored Procedures>Add New Stored Procedure
Configure Stored Procedure change name in top line http://msdn.microsoft.com/en-us/li
brary/aa258259(SQL.80).aspx http://databases.about.com/od/
sqlserver/a/storedprocedure.htm
Stored Procedures with VB start SQL Server Management
Studio Express attach or create a database file right-click database name>New Query paste in a sample query (e.g., from link
above) and modify it to match fields in this database)
run it to see results
Creating Stored Procedures start SQL Server Management Studio expand a database>expand
Programmability>right-click Stored Procedures>New Stored Procedure
click Query in top menu>Specify Values for Template Parameters
replace values for ProcedureName, @Param[], Datatypes and Default Values
Complete Stored Procedure replace SELECT statement with SQL
code for the procedure parameters usually are in WHERE clause
WHERE [field] [compare] @[name] e.g., WHERE AGE = @age
use Query>Parse to verify syntax click !Execute button to compile it File>Save (rename it)>Save
Verify Stored Procedure click Refresh icon in Object
Explorer expand [database name]>
Programmability>Stored Procedures to verify that it's there
Test Stored Procedure click New Query and type the
following:USE "database name"; 'within quotes GOEXECUTE [stored proc name] @[name] = [value], @[name2] = [value2];GO ignore warnings
click !Execute button and verify results
Sample Code uses Nations.mdf database from
Classy Project stored procedure is named
dbo.GetByPopGoldsSELECT * from nations2 where Pop > @pop and Gold <
@gold
Add Procedure to Code create a VB Project with a ListBox,
two Textboxes and a Button double click the Button to create a
Sub and add code on following pages
DeclarationsDim sqc As SqlCommandDim da As SqlDataAdapterDim ds As DataSetDim con As SqlConnectionDim dr As DataRowDim output As StringDim pads() As Integer = {4, 22, 3, 3, 3, 7, 15}Dim padDirection() As String = {"L", "R", "L", "L",
"L", "L", "R"}
Connection Codeds = New DataSetcon = New SqlConnectioncon.ConnectionString ="server=.\SQLEXPRESS;"
_ & AttachDbFilename=[path]\Nations.mdf;" _& "Integrated Security=True;"
Getting Datasqc = New SqlCommandsqc.CommandText = "Exec [dbo].[GetByPopGolds]
" _& TextBox1.Text & ", " & TextBox2.Textsqc.Connection = conda = New SqlDataAdapterda.SelectCommand = sqcda.Fill(ds)
ListBox1.Sorted = True
Load OutputsFor Each dr In ds.Tables(0).Rows output = "" For i As Integer = 0 To 6 If padDirection(i) = "L" Then output += CStr(dr(i)).PadLeft(pads(i)) & " " Else output += CStr(dr(i)).PadRight(pads(i)) End If Next ListBox1.Items.Add(output)Next
Using Optional Parameters Optional Parameters in SQL Stored
Procedures create a stored procedure based on
the code at the above web page right click the stored procedure name>
Execute Stored Procedure>either check Pass Null Value or input the desired criterion (don't do both!), OK and review output
Dynamic SQL include SQL code in parameters
rather than just values potential security risks (SQL injection)
potential to create more flexible stored procedures more options
Microsoft Access can create stored procedures in VB
code http://www.devcity.net/Articles/
18/msaccess_sp.aspx
Creating a Stored Procedure download sample.mdb into the
project folder create a query using design view
can also use query from form or report see Help on saving SQL statements as
queries
use Save As to save query within the database with the name you give it