1. Guide to Oracle10G1 Using SQL Queries to Insert, Update, Delete, and View Data Chapter 3

2. Guide to Oracle10G2 Lesson A Objectives Learn how to run a script to create database tables automatically Learn how to insert data into database tables Learn how to create database transactions and commit data to the database Create search conditions in SQL queries Understand how to update and delete database records, and how to truncate tables Learn how to create and use sequences to generate surrogate key values automatically Learn how to grant and revoke database object privileges

3. Guide to Oracle10G3 Using Scripts to Create Database Tables One or more SQL commands saved in a text file Usually have.sql extension To run from SQL*Plus: –Start full file path (c:\temp\myfile.sql) –Ex: start c:\temp\myfile.sql –@full file path (@c:\temp\myfile.sql) –Ex: @c:\temp\myfile.sql –Extension can be omitted if it is.sql

4. Guide to Oracle10G4 Inserting Data into Tables INSERT command adds new records Field values should match column order, or be specified in command INSERT INTO faculty (F_ID, F_LAST, F_FIRST, F_MI, LOC_ID) VALUES (1, 'Cox', 'Kim', 'J', 9);

5. Guide to Oracle10G5 Format Models Used to format data retrieved from database Can be used to format a date to display time or a number to display as a currency

6. Guide to Oracle10G6 Numerical Format Models

7. Guide to Oracle10G7 Date Format Models

8. Guide to Oracle10G8 Date Format Models

9. Guide to Oracle10G9 Inserting Date and Interval Values Use to_date function to convert a character string to a date –Specify date string and matching format model –TO_DATE('08/24/2004', 'MM/DD/YYYY') –TO_DATE('10:00 AM', 'HH:MI AM')

10. Guide to Oracle10G10 Creating Transactions and Committing New Data Transaction: series of action queries that represent a logical unit of work User can commit (save) changes User can roll back (discard) changes Pending transaction: a transaction waiting to be committed or rolled back Oracle DBMS locks records associated with pending transactions Other users cannot view or modify locked records

11. Guide to Oracle10G11 Commit and Roll Back in SQL*Plus Transactions begin automatically with first command Type COMMIT to commit changes Type ROLLBACK to roll back changes

12. Guide to Oracle10G12 Creating Search Conditions in SQL Queries An expression that seeks to match specific table records Used in SELECT, UPDATE and DELETE statements WHERE fieldname comparison_operator search_expression WHERE S_ID = 1

13. Guide to Oracle10G13 Comparison Operators

14. Guide to Oracle10G14 Defining Search Expressions Character strings –Must be enclosed in single quotes –Case sensitive Dates –Use to_date function with date string and format model

15. Guide to Oracle10G15 Creating Complex Search Conditions Combines multiple search conditions using the AND,OR, and NOT logical operators. AND – both conditions must be true OR – one or both condition must be true NOT – opposite of actual value Use () to group logical operators

16. Guide to Oracle10G16 Updating and Deleting Existing Table Records UPDATE: –Updates field values in one or more records in a table –Only one table may be updated at a time –UPDATE tablename SET field1= new_value1, field2 = new_value2,... WHERE search condition; DELETE: –Removes specific records from a database table –If search condition is omitted, entire table data is removed –DELETE FROM tablename WHERE search condition;

17. Guide to Oracle10G17 Updating and Deleting Existing Table Records TRUNCATE –Removes all of the table data without saving any rollback information –Must disable foreign key constraints before truncating table –TRUNCATE TABLE tablename;

18. Guide to Oracle10G18 Sequences Sequential lists of numbers to create unique surrogate key values To use a sequence: –SELECT sequence_name.NEXTVAL FROM DUAL; –INSERT INTO location LOC_ID) VALUES(loc_id_sequence.NEXTVAL);

19. Guide to Oracle10G19 Database Object Privileges Privileges must be granted so that other users can access objects in user schema GRANT privilege1, privilege2,…ON object_name TO user1,user2,...; REVOKE privilege1, privilege2,... ON object_name FROM user1, user2,...; To grant or revoke privileges for everyone use PUBLIC as user

20. Guide to Oracle10G20 Lesson B Objectives Learn how to write SQL queries to retrieve data from a single database table Create SQL queries that perform calculations on retrieved data Use SQL group functions to summarize retrieved data

21. Guide to Oracle10G21 Retrieving Data from a Single Database Table SELECT fieldname1, fieldname2,... FROM ownername.tablename WHERE search_condition; To select: –All rows omit where clause –All fields, use *: SELECT * FROM … –Only unique field values: SELECT DISTINCT fieldname Search condition: –Use comparison and logical operators –IS NULL/IS NOT NULL to match/exclude NULL values –IN/NOT IN to match set values –LIKE with wildcards % and _ to match character strings

22. Guide to Oracle10G22 Sorting Query Output Use ORDER BY sort_key_field(s) Default order is ascending, use DESC to sort descending

23. Guide to Oracle10G23 Using Calculations in SQL Queries Calculations are performed by DBMS, result only sent to client Can use arithmetic operators (+, -, *, /) Place calculation in select clause: SELECT price * quantity FROM … Calculations can be performed on NUMBER, DATE and INTERVAL fields only Single-row functions: built in Oracle functions to perform calculations and manipulate retrieved data values

24. Guide to Oracle10G24 Oracle9i SQL Group Functions Group functions: perform an operation on a group of queried rows and returns a single result

25. Guide to Oracle10G25 Group By Use to group output by the field with duplicate values and apply group functions to the grouped data

26. Guide to Oracle10G26 Having Use to place a search condition on results of group function calculations Like “WHERE” for group functions HAVING group_function comparison_operator value HAVING SUM(capacity) >= 100

27. Guide to Oracle10G27 Formatting Output in SQL*Plus To change default column headings: –Specify alternate column headings: SELECT fieldname1 "heading1_text", fieldname2 "heading2_text",... –Use an alias for column headings: SELECT fieldname1 AS alias_name1... To change SQL*Plus line and page size settings –Select Options/Environment on menu bar –Modify linesize and pagesize to desired values

28. Guide to Oracle10G28 Formatting Numbers and Dates Use to_char function with format models TO_CHAR(field_name, 'format_model') SELECT inv_id, TO_CHAR(inv_price, '$99,999.99') FROM inventory WHERE item_id = 1 ;

29. Guide to Oracle10G29 Lesson C Objectives Learn how to create SQL queries that join multiple tables Learn how to create nested SQL queries Understand how to combine query results using set operators Create and use database views

30. Guide to Oracle10G30 Joining Multiple Tables Join: combine data from multiple database tables using foreign key references SELECT field1, field2,... FROM table1, table2 WHERE table1.joinfield = table2.joinfield AND search_condition(s); If tables share field names, must prefix field in select with table name (table1.field1, table2.field1) Join condition: part of where clause indicating how tables are related (table1.foreign_key = table2.primary key) Search conditions can be added to join condition using AND operator

31. Guide to Oracle10G31 Process for Designing Complex Inner Join Queries 1.Identify all of the tables involved in the query, and label:  Display fields  Join fields  Search fields 2.Write the query  List all display fields in the SELECT clause  List all table names in the FROM clause  List all join condition links in the WHERE clause  List all search fields in the WHERE clause

32. Guide to Oracle10G32 Inner Join Join two tables based on values in one table being equal to values in another table Also known as equality join, equijoin or natural join Returns results only if records exist in both tables

33. Guide to Oracle10G33 Using a Query Design Diagram Helpful for creating complicated queries Can use a formula to derive actual query from diagram

34. Guide to Oracle10G34 Outer Joins Returns all rows in one table and matching rows in joined table Inner table: all rows are returned Outer table: matching rows are returned Outer table marked with a + in join condition inner_table.join_field = outer_table.join_field(+) Null values are inserted for fields in outer table that are not found

35. Guide to Oracle10G35 Outer Joins Limitation of inner joins: some records may be omitted if corresponding records don’t exist in one of the tables Example: retrieve records for all students, along with their corresponding ENROLLMENT information

36. Guide to Oracle10G36 Outer Joins Student 105 (Michael Connoly) does not have any ENROLLMENT records

37. Guide to Oracle10G37 Outer Joins No records retrieved for Michael:

38. Guide to Oracle10G38 Outer Joins To include records in first (inner) table, even when they do not have matching records in second (outer) table, place outer join marker (+) beside outer table name in join clause

39. Guide to Oracle10G39 Outer Joins

40. Guide to Oracle10G40 Using Set Operators To Combine Query Results Use to select data from multiple tables not connected with foreign key relationships

41. Guide to Oracle10G41 Set Operators query1 OPERATOR query2; (where operator is UNION, UNION ALL, INTERSECT, or MINUS) Both queries must have same number of select fields and same data types in same order UNION suppresses duplicate values UNION ALL includes duplicate values INTERSECT takes only matching fields MINUS takes only fields in query1 not query2

42. Guide to Oracle10G42 Creating and Using Database Views Similar to storing the result of a query in the database Based on a source query that: –can specify a subset of a single table’s fields or records –can join multiple tables Can be used to enforce security (user has access to view but not underlying table)

43. Guide to Oracle10G43 Creating and Using Database Views Views can be updateable if: –SELECT clause contains only fieldnames, no functions or calculations –cannot contain the ORDER BY, DISTINCT, or GROUP BY clauses, group functions, or set operators –search condition cannot contain a nested query Views are used like tables for selecting, inserting, updating and deleting data (only updatable views can be modified)

44. Guide to Oracle10G44 Creating and Deleting Views CREATE OR REPLACE VIEW view_name AS source_query; DROP VIEW viewname;

45. Guide to Oracle10G45 Summary Use INSERT commands to add data NUMBER, DATE data types can be converted to and from character strings using format models Database changes are made within a transaction that can be committed or rolled back Use search conditions to specify records to update, delete or select Arithmetic, logical, grouping, and built-in Oracle functions can be used to specify search conditions and manipulate data Query output can be formatted by modifying SELECT clause

46. Guide to Oracle10G46 Summary Results from more than one table related through foreign key relationships can be combined in a join Results from more than one unrelated table can be combined using set operators Queries can be “saved” by creating a view Views can be used like tables to select, insert, update and delete data