Database example using DBUtils

I guess that you saw the example which comes with DBUtils module.
ExecuteMap is demonstrated in Sub FillGradesTable:
A Map is exactly like .Net Hashtable or Dictionary. In this case the keys are the column names and the values are the values that should be assigned.

Hi Erel,

Yes thanks for that, it does provide a little help however for someone coming into Basic4Android it is somewhat limited.

I have been struggling to come to terms with DBUtils as I believe that it probably represents the best way to approach database creation in this medium however the lack of real life examples (that I have so far managed to find) make it difficult to progress. No doubt I will get there in the end, but it would be so much easier with a decent size comprehensive project as an example (i.e. one that uses all of the functions available).

Tom

DBUtils is not always the best way. It contains a set of methods for common tasks. The advantage of code modules is that you can also look into the code, learn from it and also modify it as you need.

DbUtils Map Error

Hi Erel

I am using your DbUtils module but get an error when I am running my application on Samsung SIII, below is my code.

' Procedure to read the site details from the Sites table
Sub SiteRead(sSiteID As String)
If sSiteID = "" Then Return
' check if a site exists, if so display record
Dim m As Map
m = DbUtils.ExecuteMap(SQLite, "SELECT SiteId, SiteName, SiteMobileNo, LRation FROM Sites WHERE SiteId = ?", _
Array As String(sSiteID))
If m = Null Then
' the site is not found
'edtSiteName.Text = ""
'edtCellNo.Text=""
'edtLRatio.Text = ""
Else
' put the details in the site screen
' the map uses lowercase, so change fields to lowercase
edtSiteName.Text = m.Get("sitename")
edtCellNo.Text= m.Get("sitemobileno")
edtLRatio.Text = m.Get("lration")
End If
End Sub

The error starts on the line with...
edtSiteName.Text = m.Get("sitename")
and says java.lang.RuntimeException: Object should first be initialized (Map).

I have compared my example to your student scores example and everything looks fine. Can you please advise as this works perfectly on the IDE.

Thanks a lot.

Your code looks good.
I would check your database, I am thinking what you have in the IDE is not what is on the device.

DBUtils.ExecuteMap returns an uninitialized Map when no results are found.

You should check:

Thanks Guys. I have another question regarding indexes. I have created this method.

' create an index on a table.
Sub Table_CreateIndex(TableName As String, FieldNames As String)
Dim spFields() As String = Regex.Split(",", FieldNames)
For i = 0 To spFields.Length -1
Dim field, sQry As String
field = spFields(i).trim
If field.Length > 0 Then
sQry = "CREATE INDEX IF NOT EXIST " & TableName & "_" & field & " ON [" & TableName & "] (" & field & ")"
Log("CreateIndex: " & sQry)
'SQLite.ExecNonQuery(sQry)
End If
Next
End Sub

...

but for some reason I get a null exception error when I run it, thus having commented the ExecNonQuery line. Can someone help please.

Please use [ code ] [ /code ] tags (without spaces) when posting code.

Which line raises this error?

Ok, thanks for the advice, was not aware. Its the SQLite.ExecNonQuery(sQry) line.