Drawing data diagrams - any advice will be highly appreciated

We are about to develop a program that looks much like a SQL query
builder - a number of "tables" (represented as rectangles) with some
fields inside the rectangle. Tables may also be linked with arrows of
different kind in order to indicate different kinds of relationships.
All these objects should be created by dropping them from a toolbar of
some kind. In addition one should be able to select them and move them
around. All this need not to be so advanced as programs of this class
may be, but still some basic functionality is to be implemented.

We are pretty new in doing graphics in general so we do need some advice
on how to draw (and animate) all these objects. Is there any Delphi
library that we should pay attention to? Is there any book we shoul read
first in order to avoid reinventing the wheel.

Thanks in advance.