package org.msh.reports.query;

import org.msh.reports.FilterValue;



/**
 * Generic SQL definitions used by report instances of {@link org.msh.reports.filters.Filter} and
 * {@link org.msh.reports.variables.Variable} to
 * construct the SQL query to be sent to the database
 * @author Ricardo Memoria
 *
 */
public interface SQLDefs {

	/**
	 * Return the name of the master table of the query
	 * @return
	 */
	TableJoin getMasterTable();
	
	/**
	 * Return the table join equiv
	 * @param table
	 * @return
	 */
	TableJoin table(String table);
	
	/**
	 * Create a join between a parent table (already existing table in the
	 * SQL definition) and a new target table
	 * @param newtable is the table and field name of the new table to join with
	 * @return parentTable is the table and field name of the existing table to join with
	 */
	TableJoin join(String newtable, String parentTable);
	
	TableJoin join(String newtable, String newfield, String parentTable, String parentField);
	

	/**
	 * Add a field of the master table to be returned by the query
	 * @param field is the field to be returned
	 */
	void select(String field);

	/**
	 * Add a SQL restriction to the query
	 * @param restriction
	 */
	void addRestriction(String restriction);
	
	/**
	 * Add a value to a parameter in the query 
	 * @param paramname
	 * @param value
	 */
	void addParameter(String paramname, Object value);
	
	
	/**
	 * Return the value of a filter. If filter is not in the query, so it returns null
	 * @param fielterid is the ID of the filter
	 * @return instance of the {@link FilterValue} containing its value, or null if filter was not found
	 */
	FilterValue getFilterValue(String fielterid);
}