Datenbankpraktikum - Exercises

Logical Design

In the second lesson, we map the conceptual design onto a logical design. In addition to mapping entity types and relationships, please pay particular attention to the following cases:

• how to implement specialization hierarchies;
• how to deal with attributes whose type is again structured (such as AddressT);
• how to implement static attributes;
• how to handle domains (and whether to use them at all);
• how to handle enumeration types (such as extras in Vehicle).

The Postgres manual about DDL can be found here (sections 5.1 and 5.9). In particular, read the section on inheritance. For the syntax definition how to create types and tables, see here and here.

The solutions for the logical design in the form of PostgreSQL-DDL are here (types) and here (tables).

Constraints

Define primary key, foreign key, uniqueness, not null, and semantic (check) constraints for the logical schema. See here for the relevant parts in the manual.
Solutions are here.

Updates

Execute updates (Insert, Update, Delete) on your database. Try to violate the constraints you previously defined. (There is no reference solution for this topic).

Queries

Documentation

• Queries are described in the Postgres-Manual: here and here.
• Slides with examples for analytic queries, temporary views, and recursive queries are here
• Sample code for recursive queries is here
• Sample code for analytic queries is here
• Sample code for super groups is here

Sample Data

In order to have sufficient data to test, please load a database dump containing the table definitions and data. The dump file is here (the dump file has been replaced on October 26 and should now work). Restore the dump as follows:

• create a database user cashu (if it does not yet exist)
• create a database cashdb (if it does not yet exist) owned by user cashu
• Rename the file from "cashdb-plain.txt" to "cashdb-plain.tar".
• Create the database cashdb and restore it in pgadmin3 (In the object browser, navigate to "Databases", then right-click "cashdb" and select "restore")
  . Alternatively, execute the following command in a shell or command window:

  pg_restore -c  -d cashdb -U cashu -v cashdb-plain.tar

  In case pg_restore cannot be found (may happen on Windows), execute the script pg_env.bat first. This script is usually in the installation directory of PostgreSQL.

Exercises

A page with the SQL exercises can be found here. You can also download the SQL exercises here.
Please record your own solutions in a file so that they can be compared to the reference solution later.

Solutions ...

... are here.

Transactions

Documentation about transactions is here in the manual.

The slides shown in the lecture are here
Exercises can be downloaded here.
Solutions are here.

Views

Preparation: Views are documented here.
In the exercises on views we will also cover other approaches how to implement specialization hierarchies. The script containing the table definitions for the two hierarchies (Member and Vehicle) without table inheritance are here. A script for filling the tables is here.
Exercises are here.
Reference solutions are here.

User-defined Functions and Stored Procedures

Preparation: Chapter 36, 40, 41 in the manual. We will only use SQL and PL/pgSQL as implementation languages. You thus do not need to read the sections on PL/TCL, PL/Perl and PL/Python etc.
Slides are here.
Here are exercises for functions and procedures.

Trigger

Preparation: Chapter 36 and 37 in the manual. Slides are here.
Here are the exercises for Triggers.
Solutions are here and here.

JDBC

A short introduction into JDBC is here. An introduction into JDBC on the Postgres JDBC driver page: link. Until December 12 you should have a Java development environment installed and should be familiar with it. Possible IDEs are (NetBeans, Eclipse, JDeveloper, ...). In the lab, we will show first steps with NetBeans.
Please also download a JDBC-driver for Postgres (e.g. the Type-4-driver here).
The goal of the JDBC-exercise is to complete several Java programs with the appropriate JDBC-calls. Complete the programs in the following sequence:

1. ListPersMembers.java
2. GetMembers.java
3. OpenReservations.java
4. CancelReservations.java
5. CreateInvoices.java

Solutions are here: CancelReservations.java and CreateInvoices.java