public void addField(Column c) {
		// Check if the column pk is already exist
		if(c.getName().equals(this.getNamePK())){
			int i=0;
			while(!this.setNamePK(this.getNamePK() + String.valueOf(i))){
				i++;
			}
		}
		// Check if any name is repeated
		List<Column> fields = this.getFields();
		for(Column col: fields){
			int i = 0;
			while(col.getName().equals(c.getName())){
				c.setName(col.getName() + String.valueOf(i));
				addField(c);
				i++;
				return;
			}
		}
		fields.add(c);
	}