Download Java Database Connectivity

Java Database Connectivity
By: Abe Marji
CS616
Agenda
1. Quick Review of Databases
2. What is SQL?
3. What is JDBC?
4. Advanced Functions of JDBC
5. Summary
What are Databases?
• A database is a collection of tables, which
organizes and stores information
• The columns each contain a category of
information.
• A table consists of rows (records) of columns
(fields)
• The rows contain the information for each of the
categories related to an individual event
Database Samples
Columns (Attributes)
Table 1
COL1
Rows (Data)
COL3
COL4
COL5
ROW1
ROW2
Table 2
COL2
DATA DATA
ROW3
ROW4
Relationship
DATA DATA
ROW5
ROW6
ROW7
DATA DATA
COL6
What is SQL?
• SQL is “Structure Query Language”
• It is considered to be the standard for
database handling.
• SQL provides functions to View, Update,
Delete, and Add data to a database.
• SQL also handles the database structure
such as changing the properties of its tables
or adding or delete new Tables
Types of SQL Calls
• SELECT – Queries existing Data
• UPDATE – Updates existing data
• INSERT – Adds new data in a table
• DELETE – Deletes data or tables
• CREATE – Creates new tables
Samples of SQL Queries
A simple example of an SQL statement is
Standard SQL Statement:
Format: “Function Col from condition”
“SELECT * FROM Animal“
Not Case Sensitive:
“Select NaMe from ANIMAL“
Data is Case Sensitive:
“SELECT * from CUSTOMERS where NAME =‘JOE’”
Is different from
“SELECT * from CUSTOMERS where NAME =‘Joe’”
SQL Standard Data Types
Java type
SQL Type
Values
Char
Int
Short
Long
Double
Double
Float
Byte
Java.math.BigDecimal
Java.math.BigDecimal
Char or Character
Integer
Small Integer
Big Integer
Double
Float
Real
Tiny Integer
Numeric
Decimal
String
32 Bit
16 Bit
64 Bit
15 Digits
15 Digits
7 Digits
8 Bits
Fixed Point with
decimal Digits
SQL Data Types – Other
Java type
SQL Type
Values
Boolean
Java.sql.Date
Java.sql.time
Java.sql.datestamp
Bit
Date
Time
datestamp
True/False
Month/Day/Year
Hour / Min / Sec
Date and Time
What is JDBC?
• JDBC is JAVA Database Connectivity.
• JAVA Applications uses JDBC to connect to
a Database.
• JDBC API are available from Sun Systems.
• Different Database Vendors make their own
JDBC Drivers.
JDBC Driver Layer Model
Querying through Drivers
Sun’s JDBC/ODBC Bridge
Vendor Specific JDBC Drivers
Creating an ODBC Connection
Typical JDBC Code
• import java.sql.*;
•Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
• a_connection = DriverManager.getConnection
("jdbc:odbc:CS616DB",“admin",“password");
• a_statement = a_connection.createStatement();
• ResultSet rs = a_statement.executeQuery("SQL Query”);
Sample JDBC Code
Static Connection
DriverManager.getConnection (String
datasource, String userid, String password)
Connection a_conn =
DriverManager.getConnection(“jdbc:odbc:
CS616DB”, “Admin”, “password”);
JDBC Exceptions
• Exceptions occur in Java when errors occur in
SQL code.
• Catching exceptions means dealing with those
errors.
• You can use several methods to get further
information on an SQLException:
getSQLState()
getErrorCode()
getNext Exception()
getWarnings()
Flow for JDBC Exceptions
Advanced Functions
• JDBC has the ability to support Prepared
Statements and CALL statements
• Prepared Statements lets you use one sql
statement to run different queries by passing
it different parameters.
• CALL statements allows the developer to
use database queries that are created by the
Database Admin.
Summary
• JDBC is used in applications that
require database connectivity
• Different Vendors support various
types of JDBC Drivers.
• JDBC can take advantage of
advanced SQL functions/queries
using the CALL and Execute
procedures()