Partial Reload for Fast and Selective Reloads

How many times you have loaded huge application for hours and realized you either missed a table or need to reload data in a table. But, refreshing the application takes long time. This is where Partial Reload comes into play.
Partial Reload allows Qlikview applications to add or replace selective tables into the data model while retaining already existing tables unaffected. Due to selective tables load, full reload is eliminated and reload becomes faster.

Partial Reload option is available File menu option or invoked using Ctrl+Shift+R shortcut key.

This command executes only those load and select statements that are preceded by a replace or add prefix. Other data tables remain unaffected by the command. 
Note that, It also executes any other statement (excluding normal load and select) in the script such as drop, join, keep etc.

Let's look at the usage of 2  prefixes:

ADD  - This prefix is used to add ( or create) a new table to the existing data model.

REPLACE - This prefix is used to replace an existing table in the data model. New table name should be identical to the existing table name. If the table does not exist already, new table is created and added to the data model.

ADD/REPLACE load statements are treated just like any other load statements during regular reloads. By using ONLY keyword we can restrict ADD/REPLACE load statements execution to partial reloads only. During normal reloads these ADD ONLY / REPLACE ONLY load statements are ignored.

During Partial Reload, to avoid executing any other statements apart from ADD/REPLACE loads,  we can use IsPartialReload() function. This function returns -1 (True) during partial reload and 0 (False) during normal reload.
During development or testing, if a table needs to added or reloaded without affecting other tables in the data model, use the code snippet in the first tab of the script.

We can also use  IsPartialReload() to execute any Qlikview script statements such as drop tables, drop field to manipulate the data model  or store tables in the qvw into QVDs etc.

Partial reloads are extremely useful during coding and testing phase of Qlikview dashboard. It saves lot of reload time, makes debugging and testing faster.