SQL212.3 Introduction to SQL using Oracle Module 3

SQL/212 SQL Programming Workshop 3 – Modifying Data, Managing the Database Bookstore SQL212 Module 3

SQL212 Contact Information Bookstore SQL212 Module 3 P.O. Box 6142 Laguna Niguel, CA 92607 949-489-1472 http://www.d2associates.com [email_address] Copyright 2001-2009. All rights reserved.

SQL212 Module 3 Part 1 – Modifying Data Part 2 – Managing Database Structures Part 3 – Creating Views and Indexes Part 4 -- Security Bookstore SQL212 Module 3

SQL/212 SQL Programming Part 1 – Modifying Data Bookstore SQL212 Module 3

Bookstore SQL212 Module 3 Relational Database with constraints (from text)

Data Modification Statements Insert Update Delete Bookstore SQL212 Module 3

Data Modification Statements End-user rarely sees these statements Application developer prepares these statements “behind the scenes” based on forms filled out by user Bookstore SQL212 Module 3

Insert Adds new rows to an existing table Two forms: Single Row Multi-Row Bookstore SQL212 Module 3

Single Row Insert Bookstore SQL212 Module 3 Basic Syntax: Insert [into] <table-name> Values (<value-list>)

Single Row Insert Bookstore SQL212 Module 3 Basic Example: insert into sources(source_numb, source_name, source_street) values (22,'Specialty Books', 'Canal Street')

Insert Statement Bookstore SQL212 Module 3

Sources table after Insert Bookstore SQL212 Module 3

Multi-row Insert Bookstore SQL212 Module 3 Basic Syntax: Insert [into] <table-name> Select <select-statement> We will do this after creating a new table later in this module

Update Updates fields in an existing row Bookstore SQL212 Module 3 Basic Syntax: Update <table-name> Set <field1> = new value, <field2> = new value,… Where <selection-criteria>

Update Increase Ingram prices by 10% Bookstore SQL212 Module 3 Example: Update books Set retail_price = retail_price *1.10 Where source_numb = 1

Ingram Book Prices before Update Bookstore SQL212 Module 3

Ingram Book Prices after Update Bookstore SQL212 Module 3

Delete Deletes one or more rows Bookstore SQL212 Module 3 Basic Syntax: Delete from <table-name> Where <selection-criteria>

Delete Bookstore SQL212 Module 3 Example: delete the source we added Delete from sources Where source_numb = 22

Delete Bookstore SQL212 Module 3

Sources table after Delete Bookstore SQL212 Module 3

Delete and Referential Integrity Can affect referential integrity when deleting a “parent” row Can do following with child… Cascade: delete the child row Set null: set the child’s foreign key null Set default: as above but to default value No action: don’t allow delete of parent row Referential integrity can be established when creating or modifying table structures which we will look at later in the class Bookstore SQL212 Module 3

SQL/212 SQL Programming Part 2– Managing Database Structures Bookstore SQL212 Module 3

Schemas Logical view of a database; sort of a “sub-database” – we will not cover these in this module… Catalogs Clusters Domains (somewhat like a user defined datatype) These topics are highly dependent upon the vendor DBMS and installation practices In Oracle you are logged in to your schema Bookstore SQL212 Module 3

Tables Two types Base tables Temporary tables Local (or module scope) Global (session scope) We will create base tables in this class Bookstore SQL212 Module 3

Creating Tables Use create statement Specify: Columns with data types and column constraints Table constraints Foreign key references Primary key designation Bookstore SQL212 Module 3

Data Types Int – integers or whole numbers Ex: how_many int Char – fixed length fields Ex: state char(2) Varchar/Varchar2 – variable length fields Ex: address varchar2(35) Money – money field Date/Datetime – date and time And many others – see documentation or Help Bookstore SQL212 Module 3

Create Table Bookstore SQL212 Module 3 Basic syntax: Create table <table-name> <column1> <datatype> <constraints> ,.. <column1> <datatype> <constraints> … <table constraints> Note: often preceded by a drop

Temporary Tables Bookstore SQL212 Module 3 Basic syntax: Create [global] temporary table <table-name> <rest of statement as for normal create> Note: SQL Server uses a different syntax. Just put a #in front of the table name as in #mytable. Access doesn’t have true temporary tables.

Column Constraints Primary key Not NULL CHECK clause Default Unique Bookstore SQL212 Module 3

Table Constraints Primary Key Foreign Key Compare fields against each other. I.e. ship_date >= order_date Bookstore SQL212 Module 3

But first – the Drop Statement Deletes a database “object” Drop table <table-name> Drop view <view-name> Drop index <index-name> Drop domain <domain-name> Bookstore SQL212 Module 3

Create Table Bookstore SQL212 Module 3 Example 1: Create a summary table Create table summary( isbn varchar2(20) primary key , How_many int check (how_many >= 0), Constraint isbn_fk Foreign key (isbn) references books(isbn) )

Create Summary Table Bookstore SQL212 Module 3

Constraints on Summary Table Bookstore SQL212 Module 3

Multi-row Insert Bookstore SQL212 Module 3 Basic Syntax: Insert [into] <table-name> Select <select-statement>

Multi-row Insert Bookstore SQL212 Module 3 Basic Example: (store # times each book ordered) Insert into summary(isbn, how_many) Select isbn, count(*) From orderlines Group by isbn;

Multi-row Insert Bookstore SQL212 Module 3

Bookstore SQL212 Module 3 After multi-row insert in MS Access

SQL/212 SQL Programming Part 3 – Creating Views and Indexes, Modifying Structures Bookstore SQL212 Module 3

Views Think of a view as a named query wherein the definition is stored in the database Can be read like a table Some are updateable Bookstore SQL212 Module 3

Views Bookstore SQL212 Module 3 Basic syntax: Create view <view-name> (<column-list>) As <select statement>

Creating a View Bookstore SQL212 Module 3 Example: show inventory for each book

Using Views Can be used like a table subject to various limitations Cannot insert into grouped queries, etc. Etc. Sample syntax: select column-list from employee_view Bookstore SQL212 Module 3

Using a View Bookstore SQL212 Module 3

Indexes Used to speed searches, joins, etc. Placed on: primary and foreign keys Secondary keys In commercial practice often managed by DBA’s for large databases Bookstore SQL212 Module 3

Indexes Bookstore SQL212 Module 3 Basic syntax: Create [unique] index <index-name> On <table-name> (field-name> [desc]) Note: can place index on a composite key; ex: state and city

Indexes Bookstore SQL212 Module 3 Basic example: create index state_inx on customers(customer_state) Add an index on state to speed searches and reporting

Bookstore SQL212 Module 3 After indexing on customer_state

State_inx in Oracle Bookstore SQL212 Module 3

Modifying a Table Design Applies to tables Use ALTER statement Add columns Delete columns Rename columns Add column constraints Add table constraints Bookstore SQL212 Module 3

Modifying a Table Design Bookstore SQL212 Module 3 Basic syntax: Alter <table-name> Add <field-name>, Add <table-constraint>, Modify <field-name> Etc.

Modify a Table Design Bookstore SQL212 Module 3 Example: add a phone number field alter table publishers add phone char(12);

Bookstore SQL212 Module 3 After alter publishers table

SQL/212 SQL Programming Part 4 – Security Bookstore SQL212 Module 3

Security Important DBA function Beyond scope of this course Typically controlled through Enterprise Manager or Studio GUI’s In commercial practice application security frequently controlled via own login and a “users” table or similar Bookstore SQL212 Module 3

Security Specifics can vary by product Access: workgroup administrator SQL Server: users, roles Oracle: users, roles Bookstore SQL212 Module 3

SQL Security Statements Grant Revoke Deny Bookstore SQL212 Module 3

Grant Bookstore SQL212 Module 3 Syntax: Grant <access-right> [with grant option] On <object> to <user> Note: by default only tables owners and admins can access a table. Others must be granted the relevant rights.

Access Rights Select Update Insert Delete References All privileges Bookstore SQL212 Module 3

Grant Bookstore SQL212 Module 3 Example: Give user ddurso the permission to update the employees table. Grant update On employees to ddurso

Revoke Revokes the rights Syntax similar to grant Bookstore SQL212 Module 3 [end module]

Notes Bookstore SQL212 Module 3

SQL212.3 Introduction to SQL using Oracle Module 3

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SQL212.3 Introduction to SQL using Oracle Module 3