How to resize column to content in ReportLab?

For starters i would not set the column size as you did. just pass Table the colWidths argument like this:

Table(data, colWidths=[1.9*inch] * 5)

Now to your problem. If you don't set the colWidth parameter reportlab will do this for you and space the columns according to your data. If this is not what you want, you can encapsulate your data into Paragraph's, like Bertrand said. Here is an modified example of your code:

from reportlab.lib import colors
from reportlab.lib.pagesizes import letter
from reportlab.platypus import SimpleDocTemplate, Table, TableStyle, Paragraph
from reportlab.lib.styles import getSampleStyleSheet
from reportlab.lib.units import inch
styles = getSampleStyleSheet()
doc = SimpleDocTemplate("simple_table.pdf", pagesize=letter)
elements = []

data= [['00', '01', '02', '03', '04'],
       ['10', Paragraph('Here is large field retrieve from database', styles['Normal']), '12', '13', '14'],
       ['20', '21', '22', '23', '24'],
       ['30', '31', '32', 'Here is second value', '34']]
t=Table(data)
elements.append(t)
doc.build(elements)

I think you will get the idea.