caching IBObjects

a large application uses IBOBjects to load/store data into Firebird 1.5

Apart from TIBODatabase, all the work is done by TIBOQuery.

We want to add cache ability to TIBOQuery.

We will have the following new components:

TIBODatabase_=class(TIBODatabase)

public

property CacheEnabled:boolean; // will enable caching for all queries

end;

TIBOQuery_=class(TComponent)

protected

qry:TIBOQuery;

esy:TEasyTable;

function GetHash:string;

procedure CreateCacheFile;

public

property Database:TIBODatabase_;

procedure Open;

procedure ExecSQL;

constructor Create(aOwner:TComponent); override;

destructor Destroy; override;

// all main methods of a TDataset here

end;

constructor [login to view URL](aOwner:TComponent);

begin

inherited;

qry:=[login to view URL](self);

esy:=[login to view URL](self);

end;

procedure [login to view URL];

begin

(*

pseudocode:

0. if cache disabled, call inherited code

1. if SELECT, check is the query is in the cache

2. if so, return what is in the cache

3. else

begin

call inherited code

CreateCacheFile;

end;

*)

if Pos('UPDATE',Uppercase([login to view URL]))>0 then

dataset:=qry

else if Pos('DELETE',Uppercase([login to view URL]))>0 then

dataset:=qry

else if Pos('INSERT',Uppercase([login to view URL]))>0 then

inherited Open

else if Pos('OPEN',Uppercase([login to view URL]))>0 then

begin

hash:=GetHash;

if FileExists(hash) then

LoadFromCacheFile;

end

end;

function [login to view URL]:string;

begin

(*

will return a hash depending on prepared SQL.Text. The hash will be different when

the same SQL text is fed with

The hash string is created such that it will be easy to get a list of

of all cache files that depend on table X just by looking at the hash names.

Also the current day should go into the string, so that it will be easy

to filter all hash names created before date T

*)

end;

procedure [login to view URL];

var

FileName:string;

begin

(*

FileName:=GetHash;

// the hash depends on the sql text

CreateTmpTable;

// create a temporary table of type TEasyTable having the same fields

// as the current query

FillTmpTable;

// copy data from the current query into the temporary table

SaveTmpTable;

// save the temporary table to the cache directory using FileName

*)

end;

## Deliverables

We won't handle caching aging and deleting here. The coder will provide a test EXE. I should be able to get caching just replacing TIBOQuery with TIBOQuery_ in the large application.

Delphi Ingeniería Microsoft MySQL PHP Gestión de proyectos Arquitectura de software Verificación de software Windows Desktop

Nº del proyecto: #2857246

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