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70 lines
2.9 KiB
Python
70 lines
2.9 KiB
Python
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# Sebastian Raschka, 03/2014
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# Date and Time operations in sqlite3
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import sqlite3
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sqlite_file = 'my_first_db.sqlite' # name of the sqlite database file
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table_name = 'my_table_3' # name of the table to be created
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id_field = 'id' # name of the ID column
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date_col = 'date' # name of the date column
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time_col = 'time'# name of the time column
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date_time_col = 'date_time' # name of the date & time column
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field_type = 'TEXT' # column data type
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# Connecting to the database file
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conn = sqlite3.connect(sqlite_file)
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c = conn.cursor()
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# Creating a new SQLite table with 1 column
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c.execute('CREATE TABLE {tn} ({fn} {ft} PRIMARY KEY)'\
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.format(tn=table_name, fn=id_field, ft=field_type))
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# 1) Adding a new column to save date insert a row with the current date
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# in the following format: YYYY-MM-DD
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# e.g., 2014-03-06
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c.execute("ALTER TABLE {tn} ADD COLUMN '{cn}'"\
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.format(tn=table_name, cn=date_col))
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# insert a new row with the current date and time, e.g., 2014-03-06
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c.execute("INSERT INTO {tn} ({idf}, {cn}) VALUES('some_id1', DATE('now'))"\
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.format(tn=table_name, idf=id_field, cn=date_col))
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# 2) Adding a new column to save date and time and update with the current time
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# in the following format: HH:MM:SS
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# e.g., 16:26:37
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c.execute("ALTER TABLE {tn} ADD COLUMN '{cn}'"\
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.format(tn=table_name, cn=time_col))
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# update row for the new current date and time column, e.g., 2014-03-06 16:26:37
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c.execute("UPDATE {tn} SET {cn}=TIME('now') WHERE {idf}='some_id1'"\
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.format(tn=table_name, idf=id_field, cn=time_col))
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# 3) Adding a new column to save date and time and update with current date-time
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# in the following format: YYYY-MM-DD HH:MM:SS
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# e.g., 2014-03-06 16:26:37
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c.execute("ALTER TABLE {tn} ADD COLUMN '{cn}'"\
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.format(tn=table_name, cn=date_time_col))
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# update row for the new current date and time column, e.g., 2014-03-06 16:26:37
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c.execute("UPDATE {tn} SET {cn}=(CURRENT_TIMESTAMP) WHERE {idf}='some_id1'"\
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.format(tn=table_name, idf=id_field, cn=date_time_col))
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# Database should now look like this:
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# id date time date_time
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# "some_id1" "2014-03-06" "16:42:30" "2014-03-06 16:42:30"
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# 4) Retrieve all IDs of entries between 2 date_times
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c.execute("SELECT {idf} FROM {tn} WHERE {cn} BETWEEN '2013-03-06 10:10:10' AND '2015-03-06 10:10:10'".\
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format(idf=id_field, tn=table_name, cn=date_time_col))
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all_date_times = c.fetchall()
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print('4) all entries between ~2013 - 2015:', all_date_times)
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# 5) Retrieve all IDs of entries between that are older than 1 day and 12 hrs
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c.execute("SELECT {idf} FROM {tn} WHERE DATE('now') - {dc} >= 1 AND DATE('now') - {tc} >= 12".\
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format(idf=id_field, tn=table_name, dc=date_col, tc=time_col))
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all_1day12hrs_entries = c.fetchall()
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print('5) entries older than 1 day:', all_1day12hrs_entries)
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# Committing changes and closing the connection to the database file
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conn.commit()
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conn.close()
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