database.ModuleBase

Module database :: Class ModuleBase

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Type ModuleBase

object --+
         |
        ModuleBase

Known Subclasses:: Media

Base class to implement a specific Virtual Table module with apsw. For more info: http://www.sqlite.org/cvstrac/wiki/wiki?p=VirtualTables http://www.sqlite.org/cvstrac/wiki/wiki?p=VirtualTableMethods http://www.sqlite.org/cvstrac/wiki/wiki?p=VirtualTableBestIndexMethod

Method Summary
	`__init__(self, field_names)`
	`Begin(self)`
	`BestIndex(self, constraints, orderby)` Provide information on how to best access this table.
	`Close(self)` Close a cursor previously created by Open By default, do nothing
	`Column(self, N)` Find the value for the N-th column of the current row.
	`Commit(self)`
	`Connect(self, connection, modulename, databasename, vtablename, *args)` Connect to an existing virtual table, by default it is identical to Create
	`Create(self, connection, modulename, databasename, vtablename, *args)` Called when the virtual table is created.
	`Destroy(self)` Release a connection to a virtual table and destroy the underlying table implementation.
	`Disconnect(self)` Release a connection to a virtual table.
	`Eof(self)` Determines if the current cursor points to a valid row.
	`Filter(self, idxNum, idxStr, argv)` Begin a search of a virtual table.
	`Next(self)` Move the cursor to the next row.
	`Open(self)` Create/prepare a cursor used for subsequent reading.
	`Rollback(self)`
	`Rowid(self)` Return the rowid of the current row.
	`Sync(self)`
	`UpdateChangeRow(self, rowid, newrowid, fields)` Change the row of the current rowid with the new rowid and new values
	`UpdateDeleteRow(self, rowid)` Delete row rowid
	`UpdateInsertRow(self, rowid, fields)` Insert a new row of data into the table
Inherited from object
	`__delattr__(...)` x.__delattr__('name') <==> del x.name
	`__getattribute__(...)` x.__getattribute__('name') <==> x.name
	`__hash__(x)` x.__hash__() <==> hash(x)
	`__new__(T, S, ...)` T.__new__(S, ...) -> a new object with type S, a subtype of T
	`__reduce__(...)` helper for pickle
	`__reduce_ex__(...)` helper for pickle
	`__repr__(x)` x.__repr__() <==> repr(x)
	`__setattr__(...)` x.__setattr__('name', value) <==> x.name = value
	`__str__(x)` x.__str__() <==> str(x)

Method Details

BestIndex(self, constraints, orderby)

Provide information on how to best access this table.
Must be overriden by subclass.
@param constraints: a tuple of (column #, op) defining a constraints
@param orderby: a tuple of (column #, desc) defining the order by
@returns a tuple of up to 5 values:
    0: aConstraingUsage: a tuple of the same size as constraints.
        Each item is either None, argv index(int), or (argv index, omit(Bool)).
    1: idxNum(int)
    2: idxStr(string)
    3: orderByConsumed(Bool)
    4: estimatedCost(float)

Close(self)

Close a cursor previously created by Open By default, do nothing

Column(self, N)

Find the value for the N-th column of the current row.

Parameters:: N - the N-th column

Returns:: value of the N-th column

Connect(self, connection, modulename, databasename, vtablename, *args)

Connect to an existing virtual table, by default it is identical to Create

Create(self, connection, modulename, databasename, vtablename, *args)

Called when the virtual table is created.

Parameters:: connection - an instance of apsw.Connection; modulename - string name of the module being invoked; databasename - string name of this database; vtablename - string name of this new virtual table; args - additional arguments sent from the CREATE VIRTUAL TABLE statement

Returns:: a tuple of 2 values: an sql string describing the table, and an object implementing it: Me!

Destroy(self)

Release a connection to a virtual table and destroy the underlying table implementation. By default, we do nothing.

Disconnect(self)

Release a connection to a virtual table. By default, we do nothing.

Eof(self)

Determines if the current cursor points to a valid row. The Sqlite doc is wrong on this.

Returns:: True if NOT valid row, False otherwise

Filter(self, idxNum, idxStr, argv)

Begin a search of a virtual table.

Parameters:: idxNum - int value passed by BestIndex; idxStr - string valued passed by BestIndex; argv - constraint parameters requested by BestIndex

Returns:: None

Next(self)

Move the cursor to the next row.

Returns:: None

Open(self)

Create/prepare a cursor used for subsequent reading.

Returns:: the implementor object: Me!

Rowid(self)

Return the rowid of the current row.

Returns:: the rowid(int) of the current row.

UpdateChangeRow(self, rowid, newrowid, fields)

Change the row of the current rowid with the new rowid and new values

Parameters:: rowid - rowid of the current row; newrowid - new rowid; fields - a tuple of the field values in the order declared in Create/Connect

Returns:: rowid of the new row

UpdateDeleteRow(self, rowid)

Delete row rowid

Parameters:: rowid -

Returns:: None

UpdateInsertRow(self, rowid, fields)

Insert a new row of data into the table

Parameters:: rowid - if not None, use this rowid. If None, create a new rowid; fields - a tuple of the field values in the order declared in Create/Connet

Returns:: rowid of the new row.

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