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| Deletions are marked like this. | Additions are marked like this. |
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| {{{ sage: import sqlite3 }}} |
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| This is a blank database at the moment | {{{ sage: conn = sqlite3.connect("/full/path/mydata.db") }}} |
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| This is a blank database at the moment. | |
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{{{ sage: connection.execute("CREATE TABLE cremona_label text primary key, a_0 int, a_1 int, a_2 int, a_3 int, a_4 int, a_5 int, a_6 int, rank int, regulator float)") }}} |
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| {{{ sage: E = EllipticCurve("389a") sage: connection.execute("INSERT INTO elliptic_curves(cremona_label,a_0,a_1,a_2,a_3,a_4,a_5,a_6,rank,regulator) VALUES (?,?,?,?,?,?,?,?,?,?)", ("389a",0,E.a1(),E.a2(),E.a3(),E.a4(),0,E.a6(),E.rank(),E.regular())) }}} |
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| This is our new entry in the database tempdb. | This is our new entry in the database mydata! (If this fails with a mysterious error then possibly the entries, such as E.a1(), need to be coerced into the correct data type, such as int(E.a1()).) |
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| {{{ sage: connection.execute("DELETE FROM elliptic_curves WHERE cremona_label = ?",("389a",)) }}} |
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| will return the first one (fetchall will return all). | {{{ sage: result = connection.execute("SELECT * FROM elliptic_curves WHERE rank = 2") sage: result.fetchone() }} will return the first one (replacing "fetchone" by "fetchall" will return all). |
Tom Boothby's sqlite-tutorial
How to create a simple database in sqlite using SAGE.
In SAGE, type
sage: import sqlite3
To create a filename for the database
sage: conn = sqlite3.connect("/full/path/mydata.db")This is a blank database at the moment. Now create a table with fields labeled/typed as follows:
sage: connection.execute("CREATE TABLE cremona_label text primary key, a_0 int, a_1 int, a_2 int, a_3 int, a_4 int, a_5 int, a_6 int, rank int, regulator float)")This creates a sqlite3.cursor object. Now let's enter an entry into this database
sage: E = EllipticCurve("389a")
sage: connection.execute("INSERT INTO elliptic_curves(cremona_label,a_0,a_1,a_2,a_3,a_4,a_5,a_6,rank,regulator) VALUES (?,?,?,?,?,?,?,?,?,?)", ("389a",0,E.a1(),E.a2(),E.a3(),E.a4(),0,E.a6(),E.rank(),E.regular()))This is our new entry in the database mydata! (If this fails with a mysterious error then possibly the entries, such as E.a1(), need to be coerced into the correct data type, such as int(E.a1()).)
Suppose you entered something wrong and you want to delete an entry. You use the primary key to delete an entry:
sage: connection.execute("DELETE FROM elliptic_curves WHERE cremona_label = ?",("389a",))To "query" all the elliptic curves of rank 2, type: