Introduction to Databases Karolina Muszyńska https://lagunita.stanford.edu/courses/DB/RDB/SelfPaced/courseware/ch-introduction/

Topics Why are databases important? What does a Database Management System provide? Key concepts and people The relational model

Why are databases important? Databases are incredibly prevalent - they underlie technology used by most people every day if not every hour. Databases reside behind a huge fraction of websites; they're a crucial component of telecommunications systems, banking systems, video games, and just about any other software system or electronic device that maintains some amount of persistent information. Database systems provide a number of other properties that make them exceptionally useful and convenient: reliability, efficiency, scalability, concurrency control, data abstractions, and high-level query languages.

What does a DBMS provide? DBMS provides efficient, reliable, convenient, and safe multi-user storage of and access to massive amounts of persistent data. Massive Persistent Safe Multi-user Convenient Efficient Reliable

Key concepts and people Data model Schema versus data Data definition language Data manipulation or query language DBMS implementer Database designer Database application developer Database administrator Database user

The relational model - characteristics Used by major commercial database systems Very simple model Query with high-level languages Efficient implementations

Basic constructs in the relational model Relation (table, entity) Each table has a set of named attributes (columns) Each tuple (row) has a value for each attribute Each attribute has a type (domain) Schema – structural description of relations in database (name of the table, of its columns and types) Instance – actual contents at a given point of time Null – special value for ”unknown” or ”undefined” Key – attribute whose value is unique in each row or a set of attributes whose combined values are unique

Creating and querying relational databases - steps Design schema – create using Data Definition Language – structure of the relations (tables) and attributes Bulk load –initial data (populate the database) Repeat: execute queries and modifications

Microsoft Access 2013 tutorial http://www.gcflearnfree.org/access2013 Access basics: Getting started with Access Managing Databases and Objects Working with data: Working with tables Working with forms Sorting and filtering records