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Improve data type hierarchy, add documentation

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This commit is contained in:
Lea Laux 2021-02-17 12:25:03 +01:00 committed by KDV Admin
parent f506bcbafe
commit 9f9fd245c0
2 changed files with 65 additions and 14 deletions
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75
pygadmin/csv_importer.py
View File

@ -67,11 +67,18 @@ class CSVImporter:
def assume_data_types(self):
"""
Assume the data types of the rows in the csv file based on the given values. Check the first 100 values, so the
overhead is small, but the check data is large enough to get a correct assumption. The supported data types for
assuming are NULL, INT, DECIMAL and TEXT.
Assume the data types of the rows in the csv file based on the given values. Check the first 10000 values, so
the overhead is small, but the check data is large enough to get a correct assumption. The supported data types
for assuming are NULL, INT, DECIMAL and TEXT.
"""
# Check the of the csv data without the header.
if len(self.csv_data) - 2 > 10000:
# Set the limit to 10000 in case of a larger file.
check_limit = 10000
# Set the limit to the data size of the file.
else:
check_limit = len(self.csv_data) - 2
# Create a list for the data types.
@ -84,17 +91,19 @@ class CSVImporter:
# Check the data type of the current column.
for check_column in range(len(current_row)):
# Get the old/previous data type for comparison.
old_data_type = self.data_types[check_column]
# If the data type is TEXT, break, because there is nothing to change. This data type works in every
# case.
if self.data_types[check_column] != "TEXT":
if old_data_type != "TEXT":
# Get the current value.
value = current_row[check_column]
# Get the data type of the current value.
data_type = self.get_data_type(value)
# If the data type is not null, write the data type in the data type list. # TODO: Debug this data
# type shit
if data_type != "NULL" or (self.data_types[check_column] != "REAL" and data_type == "INT"):
# If the data type is not null, write the data type in the data type list. Converting REAL to INT is
# not allowed.
if data_type != "NULL" and (not (old_data_type == "REAL" and data_type == "INT")):
self.data_types[check_column] = data_type
def get_data_type(self, value):
@ -197,60 +206,99 @@ class CSVImporter:
# Check the name of the table.
self.table_name = self.check_ddl_parameter(self.table_name)
def create_insert_queries(self):
# TODO: docu
def create_and_execute_insert_queries(self):
"""
Create the necessary queries for inserting the data in the table based on splitting the data in sub lists for
improving the performance of the insert. The attribute of the class for the csv data should not be harmed, so
a copy is used for the working process. Execute the queries after their creation.
"""
# Copy the data list, so the work data list can be used and modified.
work_data_list = copy.copy(self.csv_data)
# Delete the header, because the header does not have to be inserted.
del work_data_list[0]
# Define a chunk size for separation the work data list in those chunks. 5000 is an acceptable value between the
# two extreme cases (inserting all data in one INSERT or inserting every row/list with an own INSERT).
chunk_size = 5000
# Split the work data list in lists with the given chunk size.
work_data_list = [work_data_list[i * chunk_size:(i+1) * chunk_size]
for i in range((len(work_data_list) + chunk_size - 1) // chunk_size)]
# Iterate over every sub list in the work data list. Those sub lists contain their separate chunk of data for
# inserting.
for sub_data_list in work_data_list:
# Get the begin of an insert query.
insert_query = self.create_insert_query_begin()
# Define a list for the parameters, because the data is used as parameter in the query.
parameter_list = []
# Get one single row, so this row (count) describes exactly one row of data.
for row_count in range(len(sub_data_list)):
# Begin the query with ( for the correct SQL syntax.
value_query = "("
# Get the row with the row count.
row = sub_data_list[row_count]
# Iterate over the value count, so it is now possible to get every single value.
for value_count in range(len(row)):
# Check the comma value: an INSERT needs commas for separating the values, but only, if a new value
# follows, which is the case for every value except the last one.
if value_count != len(row)-1:
comma_value = ", "
else:
comma_value = ""
# Put the value query together. "%s" is used as placeholder for the parameter.
value_query = "{}%s{}".format(value_query, comma_value)
# Get the actual value.
value = row[value_count]
# If the value is equal to the predefined null value/type, the value is set to None. This is
# interpreted as NULL by psycopg2.
if value == self.null_type:
value = None
# Append the value to the list of parameters.
parameter_list.append(value)
# If the current row is not the last one in the sub data list, append a comma for separating the
# different value lists per insert.
if row_count != len(sub_data_list)-1:
comma_value = ", "
# If the value is the last one, use a semicolon for the end of the query.
else:
comma_value = ";"
# Put the value query together.
value_query = "{}){}".format(value_query, comma_value)
# Combine the insert query with the value query.
insert_query = "{}{}".format(insert_query, value_query)
# Execute the insert query.
self.execute_insert_query(insert_query, parameter_list)
def execute_insert_query(self, insert_query, insert_parameters):
# TODO: docu
"""
Get the query and parameters for an insert and execute it with the database query executor.
"""
self.database_query_executor.database_query = insert_query
self.database_query_executor.database_query_parameter = insert_parameters
self.database_query_executor.submit_and_execute_query()
def create_insert_query_begin(self):
# TODO: docu
"""
Create the begin of an insert query.
"""
# Begin with the INSERT INTO and the checked table name, so an formatted input is okay.
insert_query = "INSERT INTO {} (".format(self.table_name)
# Get the header for the column names.
header = self.csv_data[0]
for column_count in range(len(header)):
@ -261,11 +309,14 @@ class CSVImporter:
else:
comma_value = ""
# Insert the column name.
insert_column = "{}{}".format(header[column_count], comma_value)
insert_query = "{}{}".format(insert_query, insert_column)
# Put the query together and append the VALUES, so the next step is adding the data for inserting.
insert_query = "{}) VALUES ".format(insert_query)
# Return the begin of the query.
return insert_query
@staticmethod
@ -306,5 +357,5 @@ if __name__ == "__main__":
csv_importer.parse_csv_file()
csv_importer.assume_data_types()
csv_importer.get_create_statement()
csv_importer.create_insert_queries()
csv_importer.create_and_execute_insert_queries()

2
pygadmin/widgets/csv_import.py
View File

@ -60,7 +60,7 @@ class CSVImportDialog(QDialog):
def insert_data(self):
begin = time.time()
self.csv_importer.create_insert_queries()
self.csv_importer.create_and_execute_insert_queries()
end = time.time()
print("Runtime: {}".format(end-begin))