This document is a module on modifying data and managing databases in SQL. It covers SQL statements for inserting, updating, and deleting data. It also discusses managing database structures like creating and modifying tables, creating views and indexes. The last part covers basic security concepts in SQL like granting and revoking user privileges.

1. SQL/200
SQL Programming
Workshop 3 – Modifying Data, Managing the
Database
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2. SQL200 Contact Information
P.O. Box 6142
Laguna Niguel, CA 92607
949-489-1472
http://www.d2associates.com
slides.1@dhdursoassociates.com
Copyright 2001-2009. All rights reserved.
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3. SQL200 Module 3
• Part 1 – Modifying Data
Part 2 – Managing Database Structures
•
• Part 3 – Creating Views and Indexes
• Part 4 -- Security
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4. SQL/200
SQL Programming
Part 1 – Modifying Data
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5. Relational Database with constraints (from text)
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6. Data Modification Statements
• Insert
• Update
• Delete
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7. Data Modification Statements
• End-user rarely sees these
statements
• Application developer prepares
these statements “behind the
scenes” based on forms filled out
by user
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8. Insert
• Adds new rows to an existing table
• Two forms:
– Single Row
– Multi-Row
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9. Single Row Insert
Basic Syntax:
Insert [into] <table-name>
Values (<value-list>)
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10. Single Row Insert
Basic Example:
insert into sources(source_numb,
source_name, source_street)
values(22,'Specialty Books',
'Canal Street')
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11. Insert Statement
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12. Sources table after Insert
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13. Multi-row Insert
Basic Syntax:
Insert [into] <table-name>
Select <select-statement>
We will do this after creating a new
table later in this module
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14. Update
• Updates fields in an existing row
Basic Syntax:
Update <table-name>
Set <field1> = new value, <field2> = new value,
…
Where <selection-criteria>
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15. Update
• Increase Ingram prices by 10%
Example:
Update books
Set retail_price = retail_price
*1.10
Where source_numb = 1
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16. Ingram Book Prices before Update
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17. Ingram Book Prices after Update
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18. After update in MS Access
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19. Delete
• Deletes one or more rows
Basic Syntax:
Delete from <table-name>
Where <selection-criteria>
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20. Delete
Example:
Delete from sources
Where source_numb = 22
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21. Delete
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22. Sources table after Delete
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23. 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
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24. SQL/200
SQL Programming
Part 2– Managing Database Structures
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25. Schemas
• Logical view of a database; sort of a “sub-
database” – we will not cover these in this module
or…
– Catalogs
– Clusters
– Domains (somewhat like a user defined datatype)
• These topics are highly dependent upon the vendor
DBMS and installation practices
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26. Tables
• Base tables
• Temporary tables
– Local (or module scope)
– Global (session scope)
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27. Creating Tables
• Use create statement
• Specify:
– Columns with data types and column
constraints
– Table constraints
• Foreign key references
• Primary key designation
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28. Temporary Tables
Basic syntax:
Create [global] temporary table <table-name>
<rest of statement as for normal create>
Note: SQL Server uses a different syntax. Put a
#in front of the table name as in #mytable.
Access doesn’t have true temporary tables.
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29. 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 varchar(35)
• Money – money field; same as MS Access
currency
• Date/Datetime – date and time
• And many others – see documentation or Help
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30. Create Table
Basic syntax:
Create table <table-name>
<column1> <datatype> <constraints>
,.. <column1> <datatype> <constraints>
…
<table constraints>
Note: often preceded by a drop
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31. Column Constraints
• Primary key
Not NULL
•
• CHECK clause
• Default
Unique
•
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32. Table Constraints
• Primary Key
• Foreign Key
• Compare fields against each other. I.e.
ship_date >= order_date
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33. 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>
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34. Create Table
Example 1: Create a summary table
Create table summary(
isbn varchar(20) primary key,
How_many int check (how_many >= 0),
Constraint isbn_fk
Foreign key (isbn) references
books(isbn)
)
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35. Create Summary Table
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36. Constraints on Summary Table
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37. Multi-row Insert
Basic Syntax:
Insert [into] <table-name>
Select <select-statement>
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38. Multi-row Insert
Basic Example: (store # times each
book ordered)
Insert into
summary(isbn, how_many)
Select isbn, count(*)
From orderlines
Group by isbn;
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39. Multi-row Insert
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40. After multi-row insert in MS Access
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41. SQL/200
SQL Programming
Part 3 – Creating Views and Indexes, Modifying
Structures
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42. 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
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43. Views
Basic syntax:
Create view <view-name> (<column-list>)
As
<select statement>
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44. Creating a View
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45. 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
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46. Using a View
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47. 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
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48. Indexes
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
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49. Indexes
Basic example:
create index state_inx
on customers(customer_state)
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50. After indexing on customer_state
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51. Customers table with index
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52. State_inx in Oracle
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53. Modifying a Table Design
• Applies to tables
• Use ALTER statement
– Add columns
– Delete columns
– Rename columns
– Add column constraints
– Add table constraints
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54. Modifying a Table Design
Basic syntax:
Alter <table-name>
Add <field-name>,
Add <table-constraint>,
Modify <field-name>
Etc.
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55. Modify a Table Design
Example: add a phone number field
alter table publishers
add phone char(12);
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56. After alter publishers table
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57. SQL/200
SQL Programming
Part 4 – Security
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58. Security
• Specifics can vary by product
Access: workgroup administrator
•
• SQL Server: users, groups
• Oracle: users, roles
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59. Security
• Important DBA function
– Beyond scope of this course
– Typically controlled through the Enterprise
Managers
• In commercial practice application security
frequently controlled via own login and a
“users” table or similar
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60. SQL Security Statements
• Grant
• Revoke
• Deny
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61. Grant
Syntax:
Grant <access-right> [with grant option]
On <object> to <user>
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62. Access Rights
• Select
Update
•
• Insert
• Delete
References
•
• All privileges
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63. Grant
Example:
Grant update
On employees to ddurso
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64. Revoke
• Revokes the rights
• Syntax similar to grant
[end module]
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