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#!/usr/bin/python
"""
Module Name: csvBrowse
Description: Plug in for PythonCard application dbBrowse to provide simple CSV functionality
Constant/configuration values are currently maintained in the source code. If we are to optimise this application they should be split into seperate configuration files (as per PythonCard/Webware style guidelines)
The structure of this module should be replicated for different RDBMS so that they can be interchanged by dbBrowse - hopefully.
"""
__version__="$Revision $"[11:-2]
__date__="$Date $"
__author__="Andy Todd <andy47@halfcooked.com>"
import csv, os
class browse:
# Connection should be a dictionary with at least two keys,
# 'databasename' and 'directory'
# This is wildly different to other database modules
def __init__(self, connection):
"Setup the database connection"
self._system_tables=[]
try:
name = os.path.join(connection["directory"], connection["databasename"])
self.reader = csv.reader(file(name, "rb"))
self.headers = self.reader.next()
self._db = "ok"
self._cursor="ok"
except IOError:
self._db = None
self._cursor = None
# This one is used in getRow
self._tableName='TheOnlyTable'
def getTables(self):
"Return a list of all of the non-system tables in <database>"
return [ "TheOnlyTable" ]
def getColumns(self, tableName):
"Get the definition of the columns in tableName"
# format of dbBrowser column definitions is
# column name, data type, length (for display), nullable, key, default
columnDefs = []
for column in self.headers:
columnName = column
dataType, nullable, key, default = "varchar", "", "", ""
# Dodgy default, but it works for me
precision = 255
columnDefs.append((columnName, dataType, precision, nullable, key, default))
return columnDefs
def getQueryString(self, tableName):
"Return a SQL statement which queries all of the columns in tableName"
# only used internally, not needed for csv files
return ""
def getRow(self, tableName):
"Get a row from tableName"
if tableName!=self._tableName:
self._tableName=tableName
result = self.reader.next()
return result
def getRows(self, tableName):
"Get all of the rows from tableName"
if tableName!=self._tableName:
self._tableName=tableName
result = []
for row in self.reader:
result.append(row)
return result
if __name__ == '__main__':
# We are in an interactive session so run our test routines
# Connect to the database
connection={ 'databasename':'testfile.csv'
,'directory':'.'}
dbHolder = browse(connection)
# Return all of our table names into user_tables
user_tables = dbHolder.getTables()
# Print out the structure of each table and its first row
print "--------------------------------------------------"
for table in user_tables:
print dbHolder.getQueryString(table)
print dbHolder.getRow(table)
print "--------------------------------------------------"
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