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# Copyright (c) 2001 by Intevation GmbH |
# Copyright (c) 2001, 2002 by Intevation GmbH |
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# Authors: |
# Authors: |
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# Bernhard Herzog <[email protected]> |
# Bernhard Herzog <[email protected]> |
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# |
# |
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Currently this is basically just a wrapper around dbflib. |
Currently this is basically just a wrapper around dbflib. |
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""" |
""" |
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# Implementation strategy regarding writing to a DBF file: |
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# |
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# Most of the time Thuban only needs to read from a table and it is |
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# important that Thuban can work with read-only files. Therefore the |
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# DBF file is opened only for reading initially. Only when |
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# write_record is called we try to open the DBF file for writing as |
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# well. If that succeeds the dbf read/write DBF file will be used |
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# for all IO afterwards. |
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# |
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# It's important to use the same DBF file object for both reading |
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# and writing to make sure that reading a records after writing |
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# returns the new values. With two separate objects this wouldn't |
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# work because a DBF file object buffers some data |
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def __init__(self, filename): |
def __init__(self, filename): |
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self.filename = filename |
self.filename = filename |
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self.dbf = dbflib.DBFFile(filename) |
self.dbf = dbflib.DBFFile(filename) |
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# If true, self.dbf is open for writing. |
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self._writable = 0 |
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def Destroy(self): |
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self.dbf.close() |
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self.dbf = None |
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def record_count(self): |
def record_count(self): |
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"""Return the number of records""" |
"""Return the number of records""" |
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return self.dbf.record_count() |
return self.dbf.record_count() |
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""" |
""" |
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return self.dbf.read_record(record) |
return self.dbf.read_record(record) |
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def write_record(self, record, values): |
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"""Write the values into the record |
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The values parameter may either be a dictionary or a sequence. |
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If it's a dictionary the keys must be the names of the fields |
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and their value must have a suitable type. Only the fields |
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actually contained in the dictionary are written. Fields for |
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which there's no item in the dict are not modified. |
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If it's a sequence, all fields must be present in the right |
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order. |
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""" |
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if not self._writable: |
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new_dbf = dbflib.DBFFile(self.filename, "r+b") |
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self.dbf.close() |
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self.dbf = new_dbf |
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self._writable = 1 |
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self.dbf.write_record(record, values) |
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self.dbf.commit() |
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