by Michael Neumann (neumann@s-direknet.de)
$Id: DBI_SPEC,v 1.9 2001/05/27 12:38:24 michael Exp $
API_VERSIONUse this in your DBD driver to ensure it is used with the correct DBD API-Version
VERSIONVersion of the DBI Interface
SQL_FETCH_NEXT
SQL_FETCH_PRIOR
SQL_FETCH_FIRST
SQL_FETCH_LAST
SQL_FETCH_ABSOLUTE
Exception classes were "borrowed" from Python API 2.0.
Warning < RuntimeErrorFor important warnings like data truncation etc.
Error < RuntimeErrorBase class of all other error exceptions. Use this to catch all errors.
InterfaceError < ErrorException for errors related to the DBI interface rather than the database itself.
NotImplementedError < InterfaceErrorException raised if the DBD driver has not specified a mandantory method (not in Python API 2.0).
DatabaseError < ErrorException for errors related to the database.
Has three attributes err, errstr and state.
DataError < DatabaseErrorException for errors due to problems with the processed data like division by zero, numeric value out of range etc.
OperationalError < DatabaseErrorException for errors related to the database's operation which are not necessarily under the control of the programmer like unexpected disconnect, datasource name not found, transaction could not be processed, a memory allocation error occured during processing etc.
IntegrityError < DatabaseErrorException raised when the relational integrity of the database is affected, e.g. a foreign key check fails
InternalError < DatabaseErrorException raised when the database encounters an internal error, e.g. the cursor is not valid anymore, the transaction is out of sync.
ProgrammingError < DatabaseErrorException raised for programming errors, e.g. table not found or already exists, syntax error in SQL statement, wrong number of parameters specified, etc.
NotSupportedError < DatabaseErrorRaised if e.g. commit() is called for a database which do not support transactions.
DBI.connect( driver_url, user=nil, auth=nil, params=nil )Connect to the database specified by driver_url, which may look like "dbi:Oracle:oracle.neumann".
Returns an DBI::DatabaseHandle object, or if called with code-block,
calls this block with the new DBI::DatabaseHandle as parameter and
calls disconnect after calling the block if it was not yet disconnected by
the user.
DBI.available_drivers
Returns an Array of all available DBD driver.
The strings which represent a DBD driver are partial DSN's
(e.g. "dbi:Oracle:").
DBI.data_sources( driver )Returns all available DSN's for the driver, which is a partial DSN (e.g. "dbi:Oracle:").
DBI.disconnect_all( driver=nil )
Disconnects all active connections of driver or
all drivers if driver is nil.
connected?
Returns true if the connection was not yet disconnected
by calling disconnect, otherwise false.
disconnectDisconnects the connection.
prepare( stmt )
prepare( stmt ) {|statement_handle| aBlock}
Prepare the SQL statement stmt and return a
DBI::StatementHandle or if called with a code-block
calls the block with the handle as parameter and after that
calls #finish onto the handle to free all resources
execute( stmt, *bindvars )
execute( stmt, *bindvars ) {|statement_handle| aBlock}Executes immediately the SQL statement stmt with binding the placeholders with values given in bindvars before.
Returns a DBI::StatementHandle or if called with code-block
calls the block with the handle as parameter and after that
calls #finish onto the handle to free all resources.
do( stmt, *bindvars )
Same as execute only that no DBI::StatementHandle is
returned but the RPC (Row Processed Count).
select_one( stmt, *bindvars)Executes the statement with binding the values to the parameters and returns the first row as a reference to a Row object.
select_all( stmt, *bindvars)Executes the statement with binding the values to the parameters and returns all resulting rows.
If called as iterator the passed DBI::Row objects are only references.
tablesReturns a list of all tables and views.
ping
Returns true if the connection is active, otherwise false.
In contranst to connected?, ping tests if the connection is still active by executing some SQL or doing something else.
quote( value )Quotes the given value value database specific and returns the result.
commitCommits current transaction.
rollbackRolls the current transaction back.
transaction {|database_handle| aBlock}First commits the current transaction, then executes the given block where the parameter is the object itself (the database handle). If the block raises an exception, then it rolls the transaction back otherwise commits it.
[attr]
[attr] = val
Sets or gets the attribute attr.
An attribute can for example be "AutoCommit", which can be set to
true or false. Attributes are database dependant.
func( function, *values )Calls the driver specific extension function named by function with values as parameters.
Enumerable
bind_param( param, value, attribs=nil )
Bind param which is either a String which is then the name of the
placeholder used in the SQL statement (e.g. Oracle: "SELECT * FROM EMP WHERE ENAME = :ename")
or it is an integer which is then the number of the placeholder where counting starts at 1.
value is the value which is bound to the placeholder.
attribs is not yet used in this version, but could later be a hash containing more information like parameter type etc..
execute( *bindvars )Execute the statement but before binds the placeholders with bindvars.
finishFrees the resources for the statement. After calling finish no other operation on this statement is valid.
cancel
Frees any result set resources which were made after a call
to execute.
After calling this method, a call to one of the fetch methods
is no more valid.
column_names
Returns an Array of all column names.
column_info
Returns an Array containing Hash's, one for
each column, which describes each column.
rows
Returns the RPC (Row Processed Count) of the last executed statement, or
nil if no such exist.
fetchable?Returns true if you can fetch rows using fetch etc..
fetch
Returns a DBI::Row object, or nil if there are
no more rows to fetch.
When called as iterator, the block is called for each row
until no more row is available. Each row is passed to the
block as DBI::Row object.
Note that the returned or passed DBI::Row object is only a reference and
should be copied (dup) if it is store elsewhere.
each {|row| aBlock }Same as fetch called as iterator.
fetch_array
Returns the current row as Array or nil if no more
row is available.
Can be also called as iterator.
fetch_hash
Returns the current row as Hash or nil if no more
row is available.
Can be also called as iterator.
fetch_many( cnt )
Returns an Array of the next cnt rows, which are
stored as DBI::Row objects.
Returns nil if there are no more rows.
fetch_allSame as fetch_many only that all rows are returned.
fetch_scroll( direction, offset=1 )direction is one of the following constants:
offset is a positive or negativ number (only when SQL_FETCH_RELATIVE is used).
fetch_scroll do not automatically free the result set if no more rows are available if e.g. you get the last row.
Returns a DBI::Row object, if not possible, returns nil.
Note that the returned DBI::Row object is only a reference and
should be copied (dup) if it is stored elsewhere.
func( function, *values )Calls the driver specific extension function named by function with values as parameters.