pressagio.dbconnector¶
Classes to connect to databases.
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class
pressagio.dbconnector.DatabaseConnector(dbname, cardinality=1)[source]¶ Base class for all database connectors.
Methods
create_bigram_table(self)Creates a table for n-grams of cardinality 2. create_index(self, cardinality)Create an index for the table with the given cardinality. create_ngram_table(self, cardinality)Creates a table for n-gram of a give cardinality. create_trigram_table(self)Creates a table for n-grams of cardinality 3. create_unigram_table(self)Creates a table for n-grams of cardinality 1. delete_index(self, cardinality)Delete index for the table with the given cardinality. delete_ngram_table(self, cardinality)Deletes the table for n-gram of a give cardinality. insert_ngram(self, ngram, count)Inserts a given n-gram with count into the database. ngram_count(self, ngram)Gets the count for a given ngram from the database. ngrams(self[, with_counts])Returns all ngrams that are in the table. remove_ngram(self, ngram)Removes a given ngram from the databae. update_ngram(self, ngram, count)Updates a given ngram in the database. close_database execute_sql increment_ngram_count ngram_like_table ngram_like_table_filtered open_database unigram_counts_sum -
__init__(self, dbname, cardinality=1)[source]¶ Constructor of the base class DababaseConnector.
Parameters: - dbname : str
path to the database file or database name
- cardinality : int
default cardinality for n-grams
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create_index(self, cardinality)[source]¶ Create an index for the table with the given cardinality.
Parameters: - cardinality : int
The cardinality to create a index for.
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create_ngram_table(self, cardinality)[source]¶ Creates a table for n-gram of a give cardinality. The table name is constructed from this parameter, for example for cardinality 2 there will be a table _2_gram created.
Parameters: - cardinality : int
The cardinality to create a table for.
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delete_index(self, cardinality)[source]¶ Delete index for the table with the given cardinality.
Parameters: - cardinality : int
The cardinality of the index to delete.
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delete_ngram_table(self, cardinality)[source]¶ Deletes the table for n-gram of a give cardinality. The table name is constructed from this parameter, for example for cardinality 2 there will be a table _2_gram deleted.
Parameters: - cardinality : int
The cardinality of the table to delete.
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insert_ngram(self, ngram, count)[source]¶ Inserts a given n-gram with count into the database.
Parameters: - ngram : iterable of str
A list, set or tuple of strings.
- count : int
The count for the given n-gram.
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ngram_count(self, ngram)[source]¶ Gets the count for a given ngram from the database.
Parameters: - ngram : iterable of str
A list, set or tuple of strings.
Returns: - count : int
The count of the ngram.
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ngrams(self, with_counts=False)[source]¶ Returns all ngrams that are in the table.
Parameters: - None
Returns: - ngrams : generator
A generator for ngram tuples.
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class
pressagio.dbconnector.PostgresDatabaseConnector(dbname, cardinality=1, host='localhost', port=5432, user='postgres', password=None, connection=None)[source]¶ Database connector for postgres databases.
Methods
close_database(self)Closes the sqlite database. commit(self)Sends a commit to the database. create_bigram_table(self)Creates a table for n-grams of cardinality 2. create_database(self)Creates an empty database if not exists. create_index(self, cardinality)Create an index for the table with the given cardinality. create_ngram_table(self, cardinality)Creates a table for n-gram of a give cardinality. create_trigram_table(self)Creates a table for n-grams of cardinality 3. create_unigram_table(self)Creates a table for n-grams of cardinality 1. delete_index(self, cardinality)Delete index for the table with the given cardinality. delete_ngram_table(self, cardinality)Deletes the table for n-gram of a give cardinality. execute_sql(self, query)Executes a given query string on an open postgres database. insert_ngram(self, ngram, count)Inserts a given n-gram with count into the database. ngram_count(self, ngram)Gets the count for a given ngram from the database. ngrams(self[, with_counts])Returns all ngrams that are in the table. open_database(self)Opens the sqlite database. remove_ngram(self, ngram)Removes a given ngram from the databae. reset_database(self)Re-create an empty database. update_ngram(self, ngram, count)Updates a given ngram in the database. increment_ngram_count ngram_like_table ngram_like_table_filtered unigram_counts_sum -
__init__(self, dbname, cardinality=1, host='localhost', port=5432, user='postgres', password=None, connection=None)[source]¶ Constructor for the postgres database connector.
Parameters: - dbname : str
the database name
- cardinality : int
default cardinality for n-grams
- host : str
hostname of the postgres database
- port : int
port number of the postgres database
- user : str
user name for the postgres database
- password: str
user password for the postgres database
- connection : connection
an open database connection
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create_index(self, cardinality)[source]¶ Create an index for the table with the given cardinality.
Parameters: - cardinality : int
The cardinality to create a index for.
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class
pressagio.dbconnector.SqliteDatabaseConnector(dbname, cardinality=1)[source]¶ Database connector for sqlite databases.
Methods
close_database(self)Closes the sqlite database. commit(self)Sends a commit to the database. create_bigram_table(self)Creates a table for n-grams of cardinality 2. create_index(self, cardinality)Create an index for the table with the given cardinality. create_ngram_table(self, cardinality)Creates a table for n-gram of a give cardinality. create_trigram_table(self)Creates a table for n-grams of cardinality 3. create_unigram_table(self)Creates a table for n-grams of cardinality 1. delete_index(self, cardinality)Delete index for the table with the given cardinality. delete_ngram_table(self, cardinality)Deletes the table for n-gram of a give cardinality. execute_sql(self, query)Executes a given query string on an open sqlite database. insert_ngram(self, ngram, count)Inserts a given n-gram with count into the database. ngram_count(self, ngram)Gets the count for a given ngram from the database. ngrams(self[, with_counts])Returns all ngrams that are in the table. open_database(self)Opens the sqlite database. remove_ngram(self, ngram)Removes a given ngram from the databae. update_ngram(self, ngram, count)Updates a given ngram in the database. increment_ngram_count ngram_like_table ngram_like_table_filtered unigram_counts_sum