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There are a bewildering array (excuse the pun) of data storage structures available to you in Visual Basic. Choose from arrays, ArrayLists, SortedLists, Dictionaries, HashTables, Lists and DataTables, among others. This blog gives an example of each type of structure, and benchmarks them to show which perform best and worst.
- VB.NET Data Storage Types Compared and Benchmarked
- VB.NET Benchmarking Test of speeds of data structures
- Arrays - Visual Basic data structures
- ArrayLists and SortedLists - Visual Basic data structures
- Dictionaries and HashTables - Visual Basic data structures
- Lists - Visual Basic data structures
- Using data tables - Visual Basic data structures (this blog)
- Benchmark Results and Recommendations
Posted by Andy Brown on 24 August 2011
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Data Tables
Data tables aren't really a way of storing name/value pairs for quick access, but instead a way of storing data from a relational database in memory. I'd expect them to perform badly in these benchmarking tests (we shall see!).
My code starts by importing the appropriate namespace:
'make sure can refer to Data objects
Imports System.Data
I then create an enumeration:
Enum enumType
StringType = 1
BooleanType = 2
DateTimeType = 3
DecimalType = 4
DoubleType = 5
IntegerType = 6
CharType = 7
End Enum
The code then creates a data table with two columns: an Id column (containing a number) and a Value column containing a string of text.
Sub DataTableTest()
Dim dtTest As New DataTable
Dim dr As DataRow
Dim dc1 As DataColumn = New DataColumn("Id")
dc1.DataType = System.Type.GetType("System.Int32")
dtTest.Columns.Add(dc1)
Dim dc2 As DataColumn = New DataColumn("Value")
dc2.DataType = System.Type.GetType("System.String")
dtTest.Columns.Add(dc2)
The rest of the code to test time taken to write, sort and read values is as follows:
StartTimer()
Dim i As Integer
For i = 0 To (10 ^ RunSize) - 1
dr = dtTest.NewRow
dr("Id") = i
dr("Value") = TestCode(i)
dtTest.Rows.Add(dr)
Next
'work out how long this took
WriteTime = ElapsedTime
'store ten values for subsequent tests
StoreTenValues()
'sort using dataview
Dim dvTest As DataView = dtTest.DefaultView
dvTest.Sort = "Value"
SortTime = ElapsedTime
'third test: find 10 "random" values by number
Dim s As String
For i = (10 ^ RunSize) - 1 To 0 Step -(10 ^ (RunSize - 1))
For Each dr In dtTest.Rows
If Convert.ToInt32(dr("Id")) = i Then
Exit For
End If
Next
Next
'report how long this took
Read1Time = ElapsedTime
'fourth test: find 10 "random" values by name
For i = 0 To 9
s = TextValues(i)
For Each dr In dtTest.Rows
If Convert.ToString(dr("Value")) = s Then
Exit For
End If
Next
Next
Read2Time = ElapsedTime
'write out results of test
AddRow("Data table")
End Sub
The results of running this test are shown at the end of this blog.
- VB.NET Data Storage Types Compared and Benchmarked
- VB.NET Benchmarking Test of speeds of data structures
- Arrays - Visual Basic data structures
- ArrayLists and SortedLists - Visual Basic data structures
- Dictionaries and HashTables - Visual Basic data structures
- Lists - Visual Basic data structures
- Using data tables - Visual Basic data structures (this blog)
- Benchmark Results and Recommendations