Working with Models
Read-only model
Model is a object that encapsulate data. In Fano framework, model that can only be used to read data is encapsulate in IModelReader interface and model that write data implements IModelWriter interface.
IModelReader has two methods that implementor class must provide:
(*!----------------------------------------------
* read data from storage
*-----------------------------------------------
* @param params parameter for search/filtering
* @return model data
s *-----------------------------------------------*)
function read(const params : IModelParams = nil) : IModelResultSet;
(*!----------------------------------------------
* return data instance after read() is execute
*-----------------------------------------------
* @return model data
*-----------------------------------------------*)
function data() : IModelResultSet;
Fano Framework does not have built-in implementation of both interface as they may be specific to application need.
Write-only model
In Fano framework, model that can only be used to write data implements IModelWriter interface.
IModelWriter has two methods that implementor class must provide:
(*!----------------------------------------------
* write data to storage
*-----------------------------------------------
* @param params parameters related to data being stored
* @param data data being stored
* @return current instance
*-----------------------------------------------*)
function write(const params : IModelParams; const data : IModelParams) : IModelWriter;
Fano Framework does not have built-in implementation of both interface as they may be specific to application need.
Read write model
To make class, can read and write data, you need to implements both interface.
type
TExampleModel = class(TInterfacedObject, IModelReader, IModelWriter)
public
//implements all interface methods here
end;
Model result set
After model read data from storage, it returns instance of IModelResultSet interface instance. Data can be accessed through this interface which has several methods:
count()returns number of data currently in result set.eof()returns if current cursor pointer is at the end of result set.next()advances current cursor pointer to next data.readString()read data as string.
Display model data in View
See Working with Views to understand how model can be used inside IView instance.