cpython/Doc/lib/libsqlite3.tex

\section{\module{sqlite3} ---
         DB-API 2.0 interface for SQLite databases}

\declaremodule{builtin}{sqlite3}
\modulesynopsis{A DB-API 2.0 implementation using SQLite 3.x.}



The module defines the following:

\begin{datadesc}{PARSE_DECLTYPES}
This constant is meant to be used with the detect_types parameter of the connect function.

Setting it makes the sqlite3 module parse the declared type for each column it
returns.  It will parse out the first word of the declared type, i. e. for
"integer primary key", it will parse out "integer". Then for that column, it
will look into pysqlite's converters dictionary and use the converter function
registered for that type there.  Converter names are case-sensitive!
\end{datadesc}


\begin{datadesc}{PARSE_COLNAMES}
Setting this makes pysqlite parse the column name for each column it returns.
It will look for a string formed [mytype] in there, and then decide that
'mytype' is the type of the column. It will try to find an entry of 'mytype' in
the converters dictionary and then use the converter function found there to
return the value. The column name found in cursor.description is only the first
word of the column name, i.  e. if you use something like 'as "x [datetime]"'
in your SQL, then pysqlite will parse out everything until the first blank for
the column name: the column name would simply be "x".
\end{datadesc}

\begin{funcdesc}{connect}{database\optional{, timeout, isolation_level, detect_types, check_same_thread, factory}}
Opens a connection to the SQLite database file \var{database}. You can use
\code{":memory:"} to open a database connection to a database that resides in
RAM instead of on disk.

When a database is accessed by multiple connections, and one of the processes
modifies the database, the SQLite database is locked until that transaction is
committed. The \var{timeout} parameter specifies how long the connection should
wait for the lock to go away until raising an exception. The default for the
timeout parameter is 5.0 (five seconds). 

For the \var{isolation_level} parameter, please see TODO: link property of
Connection objects.

SQLite natively supports only the types TEXT, INTEGER, FLOAT, BLOB and NULL. If
you want to use other types, like you have to add support for them yourself.
The \var{detect_types} parameter and the using custom *converters* registered with
the module-level *register_converter* function allow you to easily do that.

\var{detect_types} defaults to 0 (i. e. off, no type detection), you can set it
to any combination of *PARSE_DECLTYPES* and *PARSE_COLNAMES* to turn type
detection on.

By default, the sqlite3 module uses its Connection class for the connect call.
You can, however, subclass the Connection class and make .connect() use your
class instead by providing your class for the \var{factory} parameter.

Consult the section `4. SQLite and Python types`_ of this manual for details.

The sqlite3 module internally uses a statement cache to avoid SQL parsing
overhead. If you want to explicitly set the number of statements that are
cached for the connection, you can set the \var{cached_statements} parameter.
The currently implemented default is to cache 100 statements.
\end{funcdesc}

\begin{funcdesc}{register_converter}{typename, callable}
Registers a callable to convert a bytestring from the database into a custom
Python type. The callable will be invoked for all database values that are of
the type \var{typename}. Confer the parameter **detect_types** of the
**connect** method for how the type detection works. Note that the case of
\var{typename} and the name of the type in your query must match!
\end{funcdesc}

\begin{funcdesc}{register_adapter}{type, callable}
Registers a callable to convert the custom Python type \var{type} into one of
SQLite's supported types. The callable \var{callable} accepts as single
parameter the Python value, and must return a value of the following types:
int, long, float, str (UTF-8 encoded), unicode or buffer.
\end{funcdesc}


\subsection{Connection Objects \label{sqlite3-Connection-Objects}}

A \class{Connection} instance has the following attributes and methods:

\begin{memberdesc}{isolation_level}
  Get or set the current isolation level.  None for autocommit mode or one
  of "DEFERRED", "IMMEDIATE" or "EXLUSIVE".  See `5. Controlling
  Transactions`_ for a more detailed explanation.
\end{memberdesc}

\begin{methoddesc}{cursor}{\optional{cursorClass}}
  The cursor method accepts a single optional parameter \var{cursorClass}.
  This is a custom cursor class which must extend \class{sqlite3.Cursor}.
\end{methoddesc}

TODO: execute*