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1 Principles of Database Systems With Internet and Java Applications Today’s Topic Chapter 8: Applications Programming for Relational Databases Instructor’s name and information goes here Please see the notes pages for more information.
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2 Overview of Java Programming n Primary presentation in recitation sections n Features of Java –class –inheritance –virtual methods –interface –dynamic class (object file) loading –javadoc document generation –packages n Compilation and execution –javac -- compiler –java -- runtime environment (jre)
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3 Interacting with databases in Java n Java Database Connectivity (JDBC) –Package java.sql includes interfaces Driver : supports the creation of a data connection Connection : represents the connection between a Java client and an SQL database server DatabaseMetaData : contains information about the database server Statement : includes methods for executing text queries PreparedStatement : represents a pre-compiled and stored query CallableStatement : used to execute SQL stored procedures ResultSet : contains the results of the execution of a select query ResultSetMetaData, contains information about a ResultSet, including the attribute names and types.
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4 JDBC Architectures
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5 Connecting to databases with Java n java.sql.Driver –no methods for users –DriverManager.Connect method create connection n java.sql.Connection –createStatement n java.sql.Statement –executeQuery returns table as ResultSet –executeUpdate returns integer update count n Examples in class
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6 Details on JDBC Connections n Loading driver classes –Class.forName(“sun.jdbc.odbc.JdbcOdbcDriver”); –Class.forName(“oracle.thin.Driver”); –Class.forName(“jdbc:z1MySQL:”); n Database connection URL –jdbc: : –protocol example jdbc:odbc:mydatabase –subname example //hostname:port/databasename //enp01.enp.fsu.edu:3306/gsim –CS Oracle URL jdbc:oracle:thin:@oracle.cs.fsu.edu:1521:cop4540
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7 Examples of JDBC Applications n See SqlFilter.java n See Web sites –http://enp01.enp.fsu.edu n See code in examples directory
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8 Executing Insert and Update Statements n Create new customer, using String + int rowcount = stmt.executeUpdate( ”insert into Customer ” +”(accountId,lastName,firstName) ” +”values (1239,’Brown’,’Mary’)”); if (rowcount == 0) // insert failed n Update –String updateSQL = “update TimeCard set “ +”TimeCard.paid = 'yes’ where “ +”paid<>'yes’”; int count = stmt.execute(updateSQL); // count is number of rows affected
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9 Executing unknown SQL n Arbitrary SQL may return table (ResultSet) or row count (int) n Statement.execute method stmt.execute(sqlStatement); result = stmt.getResultSet(); while (true) {// loop through all results if (result != null) // process result else {// result is not a ResultSet rowcount = stmt.getUpdateCount(); if (rowcount == -1) break // no more results else // process row count } result = stmt.getMoreResults()) }
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10 Review of SQL statements for BigHit n Answer questions about homework problems n Instructor will construct SQL on demand –State question in English, SQL produced by hand
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