danfickle / java-sql-query-builder

A Java SQL query builder based loosely on the query builder included with the CodeIgniter framework.

Java SQL Query Builder

This project is an SQL query builder for Java. Currently it only supports MySql. However, it programs to interfaces so should be easy to add other SQL dialects.

The project is licensed under the permissive BSD license.

This is a sample of using this project to generate queries:

/**
 * Sample of using java-sql-query-builder with various queries.
 * IMPORTANT:
 *   For clarity exception handling and cleanup is left out.
 */
static void sample() throws SQLException, ClassNotFoundException
{
	Class.forName("com.mysql.jdbc.Driver");
	Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/YourDatabase", "root", "your_password");		
	PreparedStatement stmt;
	
	QbFactory f = new QbFactoryImp();

	// Update first_name, last_name and age for a given id...
	QbUpdate up = f.newUpdateQuery();
	up.set(f.newStdField("first_name"), ":first_name")
	  .set(f.newStdField("last_name"), ":last_name")
	  .set(f.newStdField("age"), ":age")
	  .inTable("myTable")
	  .where()
	  .where(f.newStdField("id"), ":id");
	stmt = conn.prepareStatement(up.getQueryString());
	stmt.setString(up.getPlaceholderIndex(":first_name"), "John");
	stmt.setString(up.getPlaceholderIndex(":last_name"), "Citizen");
	stmt.setInt(up.getPlaceholderIndex(":age"), 32);
	stmt.setInt(up.getPlaceholderIndex(":id"), 1024);
	stmt.executeUpdate();
	
	// Delete all records with a given age value...
	QbDelete del = f.newDeleteQuery();
	del.from("myTable")
	   .where()
	   .where(f.newStdField("age"), ":age");
	stmt = conn.prepareStatement(del.getQueryString());
	stmt.setInt(del.getPlaceholderIndex(":age"), 32);
	stmt.executeUpdate();
	
	// Insert a record with the egg_hatched field set to true...
	QbInsert in = f.newInsertQuery();
	in.set(f.newStdField("egg_hatched"), ":egg_hatched")
	  .inTable("myTable");
	stmt = conn.prepareStatement(in.getQueryString());
	stmt.setBoolean(in.getPlaceholderIndex(":egg_hatched"), true);
	stmt.executeUpdate();
	
	// Simple select query, retrieves id, age and last_name for records which
	// don't have the given id...
	QbSelect sel = f.newSelectQuery();
	sel.select(f.newStdField("id"), f.newStdField("age"), f.newStdField("last_name"))
	   .from("myTable")
	   .where()
	   .where(f.newStdField("id"), QbWhereOperator.NOT_EQUALS, ":id");
	stmt = conn.prepareStatement(sel.getQueryString());
	stmt.setInt(sel.getPlaceholderIndex(":id"), 1024);
	ResultSet rs = stmt.executeQuery();
	
	while (rs.next())
	{
		System.out.println(rs.getInt("id") + ":" + rs.getInt("age") + ":" + rs.getString("last_name"));
	}
	
	// Complicated select query with join...
	sel = f.newSelectQuery();
	sel.select(f.newQualifiedField("t1", "id"), f.newQualifiedField("t2", "id"))
	   .from("t1")
	   .join("t2", f.newQualifiedField("t2", "id"), f.newQualifiedField("t1", "t1_id"), QbJoinType.LEFT)
	   .where()
	   .where(f.newStdField("age"), ":age");
	stmt = conn.prepareStatement(sel.getQueryString());
	stmt.setInt(sel.getPlaceholderIndex(":age"), 45);
	rs = stmt.executeQuery();
	// Record enumeration left out...
	
	
	// Select query with group by...
	sel = f.newSelectQuery();
	sel.select(f.newAvg(f.newStdField("age"), "avg_age"))
	   .from("myTable")
	   .groupBy(f.newStdField("first_name"))
	   .having()
	   .where(f.newStdField("avg_age"), QbWhereOperator.GREATER_THAN, ":avg_age");
	stmt = conn.prepareStatement(sel.getQueryString());
	stmt.setInt(sel.getPlaceholderIndex(":avg_age"), 50);
	rs = stmt.executeQuery();
	// Record enumeration left out...
}