Hi Subbu, A Qualifier allows a field to maintain different type of data.For example ,if 'date' is a field with quilifier ,then that date field can hold a) creation date b)sold date c)delivery date etc....
Why Does My Mucus Change Color? If you've ever stopped to look at the contents of the tissue after you've blown your nose, you may have noticed that your mucus isn't always perfectly clear. It may be yellow, green, or have a reddish or brownish tinge to it. What do those colors mean? You might have heard that yellow or green mucus is a clear sign that you have an infection, but despite that common misperception, the yellow or green hue isn't due to bacteria. When you have a cold, your immune system sends white blood cells called neutrophils rushing to the area.
Mucus is normally clear to opaque in color with any variations from this indicating that bacterial, viral or fungal microorganisms may be present. 1  Yellow Nasal Mucus: This color is often an indicator of a less severe, acute sinus infection. It can also indicate the start of a cold or flu. Yellow nasal mucus may also be a sign of an allergic reaction. A common bacteria Staphylococcus aureus is often responsible for causing markedly yellow mucus.