Comparison of Dynamic Lists and Database Resources

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See also:    Dynamic Lists, Database Resources, FPL Script Command Syntax

Dynamic lists and Database Resources are the two Verj.io elements that can be used to access relational databases. The following chart compares their features:

Feature	Dynamic List	Database Resource
Read from database	a	a
Write to database	x	a
Display as a dropdown list	a	x
Can be used with tables	Note 1	a

Note 1: when using an API based language e.g. Javascript, a list (this will be a Custom List as opposed to a Dynamic List) can be constructed from tables and vice versa. When using the FPL language, a list can be constructed from a table using the buildlistfromtable() function, but a table cannot be constructed from a list.

Each Dynamic List or Database Resource represents a single SQL statement. This SQL statement can be built automatically by the system or it can be manually created using either the Dynamic List editor or the Database Resource editor.

Dynamic Lists only support reading from a database so SELECT statements are the only SQL statements that are issued. A Dynamic List is normally built - and the SELECT statement executed - automatically by the system after all scripts have been executed and the page is being prepared for presentation.

In contrast Database Resources can issue the full range of SQL statements SELECT, UPDATE, INSERT, DELETE. The SQL statements are executed when the corresponding script command is executed as shown in the table below. This means that accesses to Database Resources are under the full control of the developer.

API based language	FPL command	SQL statements executed
DatabaseResource.fetch()	fetch	select
DatabaseResource.update()	update	update
DatabaseResource.insert()	insert	insert
DatabaseResource.delete()	delete	delete
Table.fetchtable()	fetchtable	select
Table.updatetable()	updatetable	update, insert, delete

Both Dynamic Lists and Database Resources can be created using wizards or can be created manually. Database Resources can be imported directly from the database using the Database Resource Wizard on the main Tools menu at the top of the designer window - this creates one Database Resource for each database table imported. A Dynamic List can be created from a Database Resource using the build dynamic list icon on the toolbar of the Database Resource editor.

There is no limit to the complexity that can be used in SQL statements for either Dynamic Lists or Database Resources.