Cheat sheet for Amos II
Tore Risch
November 1, 2013

Running, saving, and exiting:

What?	Documented where?	Examples
Starting Amos II top loop from console with empty database	Getting started	amos2
Saving the database on disk	Saving and quitting	save 'mydb.dmp';
Leaving Amos II top loop	Saving and quitting	quit;
Starting Amos II with saved database	Getting started	amos2 mydb.dmp
Starting Amos II from console with Java	Java interface	javaamos
Reading AmosQL statements from a file	Redirect statement	< 'myscript.amosql';

Defining types, functions, properties, and relationships:

What?	Documented where?	Examples
Defining types	Types	create type Person; create type Department; create type Course;
Defining subtype	Types	create type Student under Person;
Defining atomic property	Stored functions	create function name(Person p) -> Charstring nm as stored;
Defining unique property	Cardinality constraints	create function ssn(Person p) -> Number no key as stored;
Defining bag valued property	Stored functions	create function phones(Person p) -> Bag of Number no as stored;
Defining many-one relationship between types	Cardinality constraints	create function dept(Person p) -> Department  d as stored;
Defining many-many relationships between types	Cardinality constraints	create function teaches(Person p) -> Bag of Course c as stored;
Defining one-one relationship between types	Cardinality constraints	create function spouse(Person p) -> Person q key as stored;

Populating and updating the database

What?	Documented where?	Examples
Creating a new object bound to a temporary variable	Create objects Interface variables	create Person instances :tore;
Setting properties	Updates	set name(:tore) = "Tore"; set phone(:tore) = 12345;
Adding a property	Updates	add phone(:tore) = 6789;
Updating sets of values	Updates	add friends(:tore) = p from Person p where "Ulla" in name(parents(p));
Creating objects and setting properties	Create objects	create Person(name,ssn,phones) instances ("Ulla",58102534,321456),("Kalle",65734828,bag(987654,567890));

Querying the database

What?	Documented where?	Examples
Finding an object	Select statement	select p into :kalle from Person p where name(p)="Kalle";
Accessing properties	Function call	phones(:kalle); select phones(p) from Person p where name(p)="Tore";
String matching	String functions	select name(p) from Person p where like(name(p),"*ll*");

Inverse functions

What?	Documented where?	Examples
Defining an inverse of another function	Derived functions	create function personNamed(Charstring nm) -> Bag of Person p as select p where name(p)=nm;
Updating inverse functions	Updates	create Person instances :ville; add personNamed("Ville") = :ville;

Help

What?	Documented where?	Examples
Function documentation	Searching source code	apropos("qrt"); doc("qrt"); sourcecode("sqrt"); doc(apropos("nearest")); sourcecode(apropos("qrt"));
Functions whose source code match pattern	Searching source code	select source_text(f) from Function f , where like(source_text(f),"*sqrt(*");
Command line help	Getting started	amos2 -h javaamos -h
Current file folder	Accessing data in files	pwd(); cd("..");
Files in current file folder (matching pattern)	Accessing data in files	dir("."); dir(".","*.txt");