1 SQL Server Management Studio SQL DDL CREATE TABLE Constraints ALTER TABLE DROP TABLE The GUI way Steen Jensen, autumn 2013

 A lot of the time you will be working in the Query window  Most of the commands can be executed in a graphical way, but start training typing in the SQL commands  The management studio is huge and a lot of functionality is aimed for administrators  And now for a live demo! 2

 SQL stands for Structured Query Language and can be divided into two groups of commands: DDL: Data Definition Language for handling the structure DML: Data Manipulation Language for handling the content  In SQL Server Management Studio you will be using a dialect of SQL called T-SQL (Transact SQL), which is largely compliant with ANSI/ISO SQL standards  All queries work on objects – a fully qualified object name: [ServerName.[DatabaseName.[SchemaName.]]]ObjectName A schema can be used for separating database objects into logical groups – default schema = dbo (= database owner) An object name must always be part of a query – the rest are optional 3

 The command CREATE TABLE is used to create a table and have the below general structure: 4

 Identity: SQL Server automatically assigns a sequenced number for every inserted/new row (other DBMS’s calls this “auto_increment”) Seed is the start value, and increment how much it should be increased  Computed columns: Used for derived attributes/columns  Column constraints: Covered in chapter 6 (e.g. Primary key) 5

 Selected rules for table & column names: Capitalization: start each word with a capital letter (“camel casing”) Name length: keep names as short as possible Limit abbreviations: only use well-known abbreviations (e.g. “no” ) Eliminate spacing between words: use camel casing Avoid underscore : “tricky” to type, difficult to read (underline) 6

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 The below create command creates a table called Employees 11

 Different constraints can be added for a table  Primary key constraints: 12

 Foreign key constraints: 13

 Foreign key constraints – self-referencing: 14

 Unique constraints: Often referred as alternate keys 15

 Check constraints: Can make a lot of validation 16

 Below is a little subset of, what is possible using the check constraint 17

 Default constraints: If a value is supplied in an insert, then no default value will be used If no value is supplied in an insert, then the default value will be used 18

 Continue with your Amazon system and create the necessary tables in SQL Server Management Studio 19

 The command ALTER TABLE is used to change an existing table and have the below general structure: 20

 The below figure shows two examples of adding new fields/columns to an existing table: 21

 The command DROP TABLE is used to delete the structure and the content of an existing table: 22

 Instead of typing in SQL commands you can do it in a graphical way  Try this by following the instructions page 165bot – 170bot 23