public void AddColumn()
{
Employees emps = new Employees();
if (emps.LoadAll())
{
DataColumn col = emps.AddColumn("FullName", Type.GetType("System.String"));
col.Expression = Employees.ColumnNames.LastName + "+ ', ' + " + Employees.ColumnNames.FirstName;
string fullName;
do
{
fullName = emps.GetColumn("FullName") as string;
}while(emps.MoveNext());
}
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// Of course if( you add a column Dynamically as the code does above
// you'll have no strongly typed accessor like emps.FullName, but you
// can use GetColumn() to access dynamic columns.
//
// Never use this to access other fields in your business entity
// although it may work, it's poor programming and always use
// your ColumnNames property and not hardcoded strings when possible
//-----------------------------------------------------------
}
public void SimpleLoad()
{
// LoadAll() expects a stored proc to exist in your database
Employees emps = new Employees();
if(emps.LoadAll()) // [proc_EmployeesLoadAll]
{
// At least one row was loaded
}
// LoadAll is the same as (but maybe less efficient) than this
emps = new Employees();
if(emps.Query.Load()) // SELECT * FROM Employees
{
// At least one row was loaded
}
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// LoadAll() and Query.Load() with no Where clause yield the same results
// however, Query.Load() builds dynamic SQL, all query data is passed
// in via SqlParameters so there is no chance for hackers to attempt
// "sql injection" techniques
//-----------------------------------------------------------
}
public void FilterAndSort()
{
Employees emps = new Employees();
if (emps.LoadAll())
{
// After you load your business entity you can apply Sort and Filter,
// you could also potentially do this in the Where clause too
emps.Filter = Employees.ColumnNames.City + " = 'Berlin'";
emps.Sort = Employees.ColumnNames.LastName + " DESC";
// Filter might have "hidden" all of the rows
if (emps.RowCount > 0)
{
string lastName;
// Remember, iteration walks the DataTable.DefaultView which is
// effected by Sort and Filter, so you'll only get Employees who
// live in Berlin, and they'll fed to your MoveNext() loop in decending
// order by LastName
do
{
lastName = emps.LastName;
}while(emps.MoveNext());
}
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// Sort and Filter can be great ways to implement data grid
// filtering in your user interface when you don't want to requery
// the database, just bind your grid to emps.DefaultView
//-----------------------------------------------------------
}
}
public void SimpleLoad()
{
// LoadAll() expects a stored proc to exist in your database
Employees emps = new Employees();
if (emps.LoadAll()) // [proc_EmployeesLoadAll]
{
// At least one row was loaded
}
// LoadAll is the same as (but maybe less efficient) than this
emps = new Employees();
if (emps.Query.Load()) // SELECT * FROM Employees
{
// At least one row was loaded
}
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// LoadAll() and Query.Load() with no Where clause yield the same results
// however, Query.Load() builds dynamic SQL, all query data is passed
// in via SqlParameters so there is no chance for hackers to attempt
// "sql injection" techniques
//-----------------------------------------------------------
}
public void Iteration()
{
Employees emps = new Employees();
if (emps.LoadAll())
{
string lastName;
// Iteration walks the DataTable.DefaultView, see the FilterAndSort
// sample for further clarification.
do
{
lastName = emps.LastName;
}while(emps.MoveNext());
emps.Rewind();
do
{
lastName = emps.LastName;
}while(emps.MoveNext());
}
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// Iteration is simple, you can rewind and restart at any time
//-----------------------------------------------------------
}
public void DataSetSerialize()
{
Employees emps = new Employees();
emps.LoadAll(); // emps.RowCount = 200
emps.LastName = "Griffinski"; // Change first row
emps.GetChanges(); // emps.RowCount now = 1
string str = emps.Serialize();
// Now reload that single record into a new Employees object and Save it
Employees empsClone = new Employees();
empsClone.Deserialize(str);
empsClone.Save();
}
public void DemonstrateBulkUpdates()
{
Employees emps = new Employees();
if (emps.LoadAll())
{
// Modify the LastName column in every row
do
{
emps.LastName += "W";
}while(emps.MoveNext());
}
// Rewind and mark the first row as Deleted
//emps.Rewind();
//emps.MarkAsDeleted();
// Add a new row and fill it in
emps.AddNew();
emps.FirstName = "Jimmy";
emps.LastName = "Lunch Box";
// Save all modifications, deletes, and new rows
emps.Save();
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// This is a very nice way to work. When you generate your
// stored procedures using 'SQL_StoredProcs.vbgen' you'll find
// it is pretty smart. It makes any identity columns
// and or computed columns as OUTPUT parameters. Thus, after Save()
// any new rows or updated rows have their identity
// columns or calulated columns already in them, no
// requerying the database
//
// You never have to use a transaction when saving a single object.
// The dOOdad architecture always does this for you.
//-----------------------------------------------------------
}
public void Serialize()
{
Employees emps = new Employees();
emps.LoadAll(); // emps.RowCount = 200
emps.LastName = "Griffinski"; // Change first row
emps.GetChanges(); // emps.RowCount now = 1
string str = emps.ToXml();
// Now reload that single record into a new Employees object and Save it
Employees empsClone = new Employees();
empsClone.FromXml(str);
empsClone.Save();
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// This really only serializes the data in the embedded DataTable.
// However, the methods used in the sample above our virtual
// so you can override them.
//-----------------------------------------------------------
}
public void DataSetSerialize()
{
Employees emps = new Employees();
emps.LoadAll(); // emps.RowCount = 200
emps.LastName = "Griffinski"; // Change first row
emps.GetChanges(); // emps.RowCount now = 1
string str = emps.Serialize();
// Now reload that single record into a new Employees object and Save it
Employees empsClone = new Employees();
empsClone.Deserialize(str);
empsClone.Save();
}
public void Serialize()
{
Employees emps = new Employees();
emps.LoadAll(); // emps.RowCount = 200
emps.LastName = "Griffinski"; // Change first row
emps.GetChanges(); // emps.RowCount now = 1
string str = emps.ToXml();
// Now reload that single record into a new Employees object and Save it
Employees empsClone = new Employees();
empsClone.FromXml(str);
empsClone.Save();
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// This really only serializes the data in the embedded DataTable.
// However, the methods used in the sample above our virtual
// so you can override them.
//-----------------------------------------------------------
}
public void AddColumn()
{
Employees emps = new Employees();
if(emps.LoadAll())
{
DataColumn col = emps.AddColumn("FullName", Type.GetType("System.String"));
col.Expression = Employees.ColumnNames.LastName + "+ ', ' + " + Employees.ColumnNames.FirstName;
string fullName;
do
fullName = emps.GetColumn("FullName") as string;
while(emps.MoveNext());
}
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// Of course if( you add a column Dynamically as the code does above
// you'll have no strongly typed accessor like emps.FullName, but you
// can use GetColumn() to access dynamic columns.
//
// Never use this to access other fields in your business entity
// although it may work, it's poor programming and always use
// your ColumnNames property and not hardcoded strings when possible
//-----------------------------------------------------------
}
public void DemonstrateBulkUpdates()
{
Employees emps = new Employees();
if(emps.LoadAll())
{
// Modify the LastName column in every row
do
emps.LastName += "W";
while(emps.MoveNext());
}
// Rewind and mark the first row as Deleted
//emps.Rewind();
//emps.MarkAsDeleted();
// Add a new row and fill it in
emps.AddNew();
emps.FirstName = "Jimmy";
emps.LastName = "Lunch Box";
// Save all modifications, deletes, and new rows
emps.Save();
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// This is a very nice way to work. When you generate your
// stored procedures using 'SQL_StoredProcs.vbgen' you'll find
// it is pretty smart. It makes any identity columns
// and or computed columns as OUTPUT parameters. Thus, after Save()
// any new rows or updated rows have their identity
// columns or calulated columns already in them, no
// requerying the database
//
// You never have to use a transaction when saving a single object.
// The dOOdad architecture always does this for you.
//-----------------------------------------------------------
}
public void FilterAndSort()
{
Employees emps = new Employees();
if(emps.LoadAll())
{
// After you load your business entity you can apply Sort and Filter,
// you could also potentially do this in the Where clause too
emps.Filter = Employees.ColumnNames.City + " = 'Berlin'";
emps.Sort = Employees.ColumnNames.LastName + " DESC";
// Filter might have "hidden" all of the rows
if(emps.RowCount > 0)
{
string lastName;
// Remember, iteration walks the DataTable.DefaultView which is
// effected by Sort and Filter, so you'll only get Employees who
// live in Berlin, and they'll fed to your MoveNext() loop in decending
// order by LastName
do
lastName = emps.LastName;
while(emps.MoveNext());
}
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// Sort and Filter can be great ways to implement data grid
// filtering in your user interface when you don't want to requery
// the database, just bind your grid to emps.DefaultView
//-----------------------------------------------------------
}
}
public void Iteration()
{
Employees emps = new Employees();
if(emps.LoadAll())
{
string lastName;
// Iteration walks the DataTable.DefaultView, see the FilterAndSort
// sample for further clarification.
do
lastName = emps.LastName;
while(emps.MoveNext());
emps.Rewind();
do
lastName = emps.LastName;
while(emps.MoveNext());
}
//-----------------------------------------------------------
// Moral:
//-----------------------------------------------------------
// Iteration is simple, you can rewind and restart at any time
//-----------------------------------------------------------
}
