Today’s part will be a slight deviation from what I planned last time. I got side-tracked with trying to save the xml file in a compressed format and actually managed to achieve it.

DotNetZip library

Thanks to this open source library it is possible to output the xml generated by the DataSet straight to a zip file – it is not necessary to first save the xml file and then zip it. To achieve this all you need is the following:

private void WriteToZipFile(string zipFilePath, DataSet ds)
{

MemoryStream mStream = new MemoryStream();
ds.WriteXml(mStream, XmlWriteMode.WriteSchema);
mStream.Seek(0, SeekOrigin.Begin);

if (File.Exists(zipFilePath))

File.Delete(zipFilePath);

using (ZipFile zipFile = new ZipFile(zipFilePath))
{

zipFile.CompressionLevel = Ionic.Zlib.CompressionLevel.BestCompression;
zipFile.AddEntry(ds.DataSetName + “.xml”, mStream);
zipFile.Save();

}

}

private Stream ReadFromZipFile(string zipFilePath, string dsName)
{

MemoryStream mStream = new MemoryStream();
using (ZipFile zipFile = new ZipFile(zipFilePath))
{

if ((from z in zipFile.Entries
where z.FileName == dsName + “.xml”
select z).Count() > 0)
{

ZipEntry ze = (from z in zipFile.Entries
where z.FileName == dsName + “.xml”
select z).First();

ze.Extract(mStream);
mStream.Seek(0, SeekOrigin.Begin);

}

}

return mStream;

}

Using it is as simple as this:

DatabaseTest dbt = new DatabaseTest(); // Typed DataSet
…
//Saving
WriteToZipFile(“SomeFileName.zip”, dbt);

//Loading
DatabaseTest dbt2 = new DatabaseTest();
dbt2.ReadXml(ReadFromZipFile(“SomeFileName.zip”, dbt.DataSetName), XmlReadMode.IgnoreSchema); //Important to ‘exclude’ the schema for a typed DataSet

Really simple hey? Since xml is very ‘compressionable’ (like most text files) you can save quite a bit on disk space.

Find a copy of it here.

WriteToZipFile(saveFileDialogXml.FileName + ".zip", dbt);

Last time I stopped with the sample code how to produce a DataSet in code and then save and load it from a file. This time I’ll just continue with the ‘typed’ DataSet version plus show what the output would look like. Interestingly, the output of both the untyped and typed versions looks (essentially) the same.

First I’ll show how the Typed DataSet version works. Just to refresh the old minds – to create a Typed DataSet you use Visual Studio’s new template for a DataSet xsd and then use the designer to add tables, columns and relationships. Then in code you can do the following (the DataSet is named ‘DatabaseTest’):

DatabaseTest dbt = new DatabaseTest();
DatabaseTest.SurnameRow surname = (DatabaseTest.SurnameRow)dbt.Surname.NewRow();
surname.Surname = “Henning”;
surname.TS = DateTime.Now;
dbt.Surname.AddSurnameRow(surname);
surname = (DatabaseTest.SurnameRow)dbt.Surname.NewRow();
surname.Surname = “Van Der Merwe”;
surname.TS = DateTime.Now;
dbt.Surname.AddSurnameRow(surname);

DatabaseTest.PersonRow pa = (DatabaseTest.PersonRow)dbt.Person.NewRow();
pa.FirstName = “Daddy Koos”;
pa.SurnameId = 1;
pa.TS = DateTime.Now;
pa.YearOfBirth = 1945;
dbt.Person.AddPersonRow(pa);

DatabaseTest.PersonRow ma = (DatabaseTest.PersonRow)dbt.Person.NewRow();
ma.FirstName = “Mommy Johanna”;
ma.SurnameId = 2;
ma.TS = DateTime.Now;
ma.YearOfBirth = 1950;
dbt.Person.AddPersonRow(ma);

DatabaseTest.PersonRow guy = (DatabaseTest.PersonRow)dbt.Person.NewRow();
guy.FirstName = “Little Koos”;
guy.SurnameId = 1;
guy.TS = DateTime.Now;
guy.YearOfBirth = 1971;
guy.FatherID = 1;
guy.MotherID = 2;
guy.ChildNo = 1;
dbt.Person.AddPersonRow(guy);

if (saveFileDialogXml.ShowDialog() == System.Windows.Forms.DialogResult.OK)
{

if (System.IO.File.Exists(saveFileDialogXml.FileName))

System.IO.File.Delete(saveFileDialogXml.FileName);

dbt.WriteXml(saveFileDialogXml.FileName, XmlWriteMode.WriteSchema);

var people = (from p in dbt.Person
join s in dbt.Surname on p.SurnameId equals s.Id
select new
{

PersonId = p.Id,
FirstName = p.FirstName,
Surname = s.Surname

});
StringBuilder sb = new StringBuilder();
foreach (var p in people)
{

sb.AppendLine(string.Format(“{0} {1}”, p.FirstName, p.Surname));

}
MessageBox.Show(sb.ToString());

System.Diagnostics.Process pro = new System.Diagnostics.Process();
pro.StartInfo = new System.Diagnostics.ProcessStartInfo(System.IO.Path.Combine(System.Environment.GetFolderPath(Environment.SpecialFolder.System), “notepad.exe”));
pro.StartInfo.Arguments = “\”” + saveFileDialogXml.FileName + “\””;
pro.Start();

}

This provides the same functionality as before. The output looks something like this (sorry, I’m a bit lazy to format/indend the output too much now):

<?xml version=”1.0″ standalone=”yes”?>
<DatabaseTest xmlns=”http://tempuri.org/DatabaseTest.xsd”>
<xs:schema id=”DatabaseTest” targetNamespace=”http://tempuri.org/DatabaseTest.xsd” xmlns:mstns=”http://tempuri.org/DatabaseTest.xsd” xmlns=”http://tempuri.org/DatabaseTest.xsd” xmlns:xs=”http://www.w3.org/2001/XMLSchema” xmlns:msdata=”urn:schemas-microsoft-com:xml-msdata” attributeFormDefault=”qualified” elementFormDefault=”qualified”>
<xs:element name=”DatabaseTest” msdata:IsDataSet=”true” msdata:UseCurrentLocale=”true”>
<xs:complexType>
<xs:choice minOccurs=”0″ maxOccurs=”unbounded”>
<xs:element name=”Person“>
<xs:complexType>
<xs:sequence>
<xs:element name=”Id” msdata:AutoIncrement=”true” msdata:AutoIncrementSeed=”1″ type=”xs:int” />
<xs:element name=”FirstName” type=”xs:string” />
<xs:element name=”SurnameId” type=”xs:int” />
<xs:element name=”Description” type=”xs:string” minOccurs=”0″ />
<xs:element name=”YearOfBirth” type=”xs:int” minOccurs=”0″ />
<xs:element name=”MonthOfBirth” type=”xs:unsignedByte” minOccurs=”0″ />
<xs:element name=”DayOfBirth” type=”xs:unsignedByte” minOccurs=”0″ />
<xs:element name=”TS” type=”xs:dateTime” />
<xs:element name=”FatherID” type=”xs:int” minOccurs=”0″ />
<xs:element name=”MotherID” type=”xs:int” minOccurs=”0″ />
<xs:element name=”PlaceOfBirthId” type=”xs:int” minOccurs=”0″ />
<xs:element name=”YearOfDeath” type=”xs:int” minOccurs=”0″ />
<xs:element name=”MonthOfDeath” type=”xs:unsignedByte” minOccurs=”0″ />
<xs:element name=”DayOfDeath” type=”xs:unsignedByte” minOccurs=”0″ />
<xs:element name=”PlaceOfDeathId” type=”xs:int” minOccurs=”0″ />
<xs:element name=”GenealogicalNo” type=”xs:string” minOccurs=”0″ />
<xs:element name=”ChildNo” type=”xs:unsignedByte” default=”0″ minOccurs=”0″ />
<xs:element name=”ProgenitorCode” type=”xs:string” minOccurs=”0″ />
<xs:element name=”IsProgenitor” type=”xs:boolean” minOccurs=”0″ />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name=”Surname“>
<xs:complexType>
<xs:sequence>
<xs:element name=”Id” msdata:AutoIncrement=”true” msdata:AutoIncrementSeed=”1″ type=”xs:int” />
<xs:element name=”Surname” type=”xs:string” />
<xs:element name=”TS” type=”xs:dateTime” />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name=”Place“>
<xs:complexType>
<xs:sequence>
<xs:element name=”Id” msdata:AutoIncrement=”true” msdata:AutoIncrementSeed=”1″ type=”xs:int” />
<xs:element name=”Place” type=”xs:string” />
<xs:element name=”TS” type=”xs:dateTime” />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name=”Marriage“>
<xs:complexType>
<xs:sequence>
<xs:element name=”Id” msdata:AutoIncrement=”true” msdata:AutoIncrementSeed=”1″ type=”xs:int” />
<xs:element name=”No” type=”xs:unsignedByte” default=”0″ minOccurs=”0″ />
<xs:element name=”HusbandId” type=”xs:int” />
<xs:element name=”WifeId” type=”xs:int” />
<xs:element name=”YearOfMarriage” type=”xs:int” minOccurs=”0″ />
<xs:element name=”MonthOfMarriage” type=”xs:unsignedByte” minOccurs=”0″ />
<xs:element name=”DayOfMarriage” type=”xs:unsignedByte” minOccurs=”0″ />
<xs:element name=”PlaceOfMarriageId” type=”xs:int” minOccurs=”0″ />
<xs:element name=”YearOfDivorce” type=”xs:int” minOccurs=”0″ />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:choice>
</xs:complexType>
<xs:unique name=”Constraint1″ msdata:PrimaryKey=”true”>
<xs:selector xpath=”.//mstns:Person” />
<xs:field xpath=”mstns:Id” />
</xs:unique>
<xs:unique name=”Surname_Constraint1″ msdata:ConstraintName=”Constraint1″ msdata:PrimaryKey=”true”>
<xs:selector xpath=”.//mstns:Surname” />
<xs:field xpath=”mstns:Id” />
</xs:unique>
<xs:unique name=”Constraint2″>
<xs:selector xpath=”.//mstns:Surname” />
<xs:field xpath=”mstns:Surname” />
</xs:unique>
<xs:unique name=”Place_Constraint1″ msdata:ConstraintName=”Constraint1″ msdata:PrimaryKey=”true”>
<xs:selector xpath=”.//mstns:Place” />
<xs:field xpath=”mstns:Id” />
</xs:unique>
<xs:unique name=”Place_Constraint2″ msdata:ConstraintName=”Constraint2″>
<xs:selector xpath=”.//mstns:Place” />
<xs:field xpath=”mstns:Place” />
</xs:unique>
<xs:unique name=”Marriage_Constraint1″ msdata:ConstraintName=”Constraint1″ msdata:PrimaryKey=”true”>
<xs:selector xpath=”.//mstns:Marriage” />
<xs:field xpath=”mstns:Id” />
</xs:unique>
<xs:keyref name=”FK_Person_Marriage” refer=”Constraint1″>
<xs:selector xpath=”.//mstns:Marriage” />
<xs:field xpath=”mstns:HusbandId” />
</xs:keyref>
<xs:keyref name=”FK_Person_Marriage1″ refer=”Constraint1″>
<xs:selector xpath=”.//mstns:Marriage” />
<xs:field xpath=”mstns:WifeId” />
</xs:keyref>
<xs:keyref name=”FK_Person_Person1″ refer=”Constraint1″>
<xs:selector xpath=”.//mstns:Person” />
<xs:field xpath=”mstns:MotherID” />
</xs:keyref>
<xs:keyref name=”FK_Person_Surname” refer=”Surname_Constraint1″>
<xs:selector xpath=”.//mstns:Person” />
<xs:field xpath=”mstns:SurnameId” />
</xs:keyref>
<xs:keyref name=”FK_Place_Person” refer=”Place_Constraint1″>
<xs:selector xpath=”.//mstns:Person” />
<xs:field xpath=”mstns:PlaceOfBirthId” />
</xs:keyref>
<xs:keyref name=”FK_Person_Person” refer=”Constraint1″>
<xs:selector xpath=”.//mstns:Person” />
<xs:field xpath=”mstns:FatherID” />
</xs:keyref>
</xs:element>
</xs:schema>

<Person>
<Id>1</Id>
<FirstName>Daddy Koos</FirstName>
<SurnameId>1</SurnameId>
<YearOfBirth>1945</YearOfBirth>
<TS>2011-06-06T09:15:58.0021555+02:00</TS>
<ChildNo>0</ChildNo>
</Person>
<Person>
<Id>2</Id>
<FirstName>Mamma Johanna</FirstName>
<SurnameId>2</SurnameId>
<YearOfBirth>1950</YearOfBirth>
<TS>2011-06-06T09:52:51.4151521+02:00</TS>
<ChildNo>0</ChildNo>
</Person>
<Person>
<Id>3</Id>
<FirstName>Little Koos</FirstName>
<SurnameId>1</SurnameId>
<YearOfBirth>1971</YearOfBirth>
<TS>2011-06-06T09:52:51.4151521+02:00</TS>
<FatherID>1</FatherID>
<MotherID>2</MotherID>
<ChildNo>1</ChildNo>
</Person>

<Surname>
<Id>1</Id>
<Surname>Henning</Surname>
<TS>2011-06-06T09:15:57.9771555+02:00</TS>
</Surname>
<Surname>
<Id>2</Id>
<Surname>Van Der Merwe</Surname>
<TS>2011-06-06T09:52:51.4121521+02:00</TS>
</Surname>

</DatabaseTest>

As you can see the xsd is actually embedded inside the xml file. This is helpful to see the structure of the data.

Next step

The next step is to create a Data Access Layer because dealing with a DataSet directly in code is so… old fashioned… and so on. Stay tuned for the next iteration.