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Re: JDBC - Need to declare variables for values in insert statement

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Here's a small, but complete code example - Bob

package us.tsos.dbs.pg;

import java.sql.*;

/**
 * This is an effort to get a computed value from a Java function
 * (or data object) included properly in the VALUES entries.
 * So, how can I declare an SQL variable and set its value to some Java value?
 * Results viewed in pgAdmin3  with query 'select * from public.hello'.
 *
 * Jar in classpath is postgresql-9.2-1002.jdbc4.jar
 * 
 * @version 0.1  Mon Jan 28 EST 2013
 * @author Bob Futrelle
 */

public class JDBCVariableTest {

Connection db;
Statement st;
Boolean boo;

public static void main(String[] args) throws SQLException {

JDBCVariableTest testIt = new JDBCVariableTest();
testIt.helloVariables();
}

public int f1() { return 3;}

public void helloVariables() throws SQLException  {

int intVar = f1();  // OK in Java, but SQL/JDBC?

try {
db = DriverManager.getConnection("jdbc:postgresql:Articles", "robertfutrelle", "<my pw>");
st = db.createStatement();
boo  = st.execute("CREATE TABLE IF NOT EXISTS hello ( Name VARCHAR NOT NULL PRIMARY KEY, value int)");

// Declare ....  ??
// INSTEAD OF THE LITERAL 4 VALUE (which works)
// how do I declare a variable and assign the f1() return value to it
// and then include it so the value 3 appears in the inserted record?
//st.execute("insert into hello values('aKey',4)");
st.execute("insert into hello values('bKey',4)");
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}



On Mon, Jan 28, 2013 at 8:39 AM, Dave Cramer <pg@xxxxxxxxxxxxx> wrote:
Bob,

Can you provide a snippet of code so I can understand what you mean by declare ?


Dave Cramer

dave.cramer(at)credativ(dot)ca
http://www.credativ.ca


On Mon, Jan 28, 2013 at 7:11 AM, Bob Futrelle <bob.futrelle@xxxxxxxxx> wrote:
Do the declare statements and insert all have to be done in one statement execute()?
That is, what is the scope of variables I declare?
I see a variety of syntax examples, some for older versions?
I'm using pg 9.2.2, so what are the rules/syntax for declaring and using variables?

Use case: I collect metadata from XML articles such as title, journalName, volume, year.  For each article I need to create a pg table record and insert the values for the various metadata items in the article.

This is my first post to this list.

Thanks,

 - Bob




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