internals:pdo:brainstorming

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
Last revisionBoth sides next revision
internals:pdo:brainstorming [2010/01/08 21:11] – external edit 127.0.0.1internals:pdo:brainstorming [2010/06/26 18:13] – PDO support for PQexecParams? eis_os
Line 85: Line 85:
   * error handling   * error handling
   * nested transaction (emulation)   * nested transaction (emulation)
 +
 +
 +=== Parameter Binding without Preparing ===
 +Allow prepareless binding of parameters for queries, like PostgreSQL PQexecParams.
 +  * queryParam() ?
 +
 +
 +
  
 ===== PDO Binding behaviour (5.3) ===== ===== PDO Binding behaviour (5.3) =====
Line 111: Line 119:
 for all bindValue/bindParam/execute input for all bindValue/bindParam/execute input
  
 +
 +=== Why do we need improvements to binding? ===
 +Currently has no standard or agreement how parameters like PDO_PARAM_BOOL should be handled on the user side or the internal PDO drivers.
 +There are even disagreements between PDOs code comment, explaining PDO_PARAM_INT is the internal PHP type, and the manual telling us it's the database native type.
 +The result is there is no agreement how even simple parameters should be bound properly and so each driver does it's own guessing how parameters are handled.
 +
 +=== The current situation ===
 +There are two basic categories how currently driver handle bindings:
 +Trying to guess the right meaning by the zval type (even if PDO is told to use a certain type)
 +Or try to convert it to string and let the database handle most stuff.
 +
 +So each driver needs some special care when binding, generally for PDO mysql you need to cast to the right type as setting the binding type constant has no affect.
 +The PDO core already convert doubles to string in the pdo_stmt.c really_register_bound_param function.
 +The current code may or may not separate the zval, so the contents of the variable may change after a successful binding or executing of a statement.
 +
 +
 +=== Proposal ===
 +PDO should enforce the zval type in really_register_bound_param so drivers will get a pre-filtered parameters
 +
 +This would mean: 
 +PDO_PARAM_* will map to internal PHP types, as the code comments in the enum pdo_param_type already tells us.
 +PDO_PARAM_ZVAL will be introduced to user space to let zvals pass directly.
 +
 +If the zval type isn't right, PDO should do a zval separation before converting so no user space variables will be altered.
 +
 +PDO_PARAM_DOUBLE should be introduced later to complete the current support.
 +
 +
 +=== Problems ===
 +PostgreSQL: Currently it's possible to pass a string like "NO" with PDO::PARAM_BOOL,
 +the string contents will be evaluated by the pdo driver, so "no" gets the equivalent of zend false.
 +
 +As soon as PDO Core enforces types and simply use convert_to_boolean bindValue(':foo', 'NO', PDO::PARAM_BOOL) would result into zend true, passed to pdo postgre it would store true! 
 +
 +But as bindValue defaults to PDO::PARAM_STR and so currently with PostgreSQL you don't need PDO::PARAM_BOOL the impact on current software shouldn't be big.
 +
 +
 +=== Workarounds ===
 +Possible workaround: A special convert_to_boolean function to support SQL FALSE and NO as zend false, however this would be unnatural to PHP core.
 +
 +
 +=== Matrix ===
 | zval/PDO           ^ PDO_PARAM_NULL  ^ PDO_PARAM_BOOL     ^ PDO_PARAM_INT     ^ PDO_PARAM_STR           ^ PDO_PARAM_LOB           ^ PDO_PARAM_AUTO (new)    ^ | zval/PDO           ^ PDO_PARAM_NULL  ^ PDO_PARAM_BOOL     ^ PDO_PARAM_INT     ^ PDO_PARAM_STR           ^ PDO_PARAM_LOB           ^ PDO_PARAM_AUTO (new)    ^
 ^ IS_NULL            | - no convert -  | SQL_NULL           | SQL_NULL          | SQL_NULL                | SQL_NULL                | SQL_NULL                | ^ IS_NULL            | - no convert -  | SQL_NULL           | SQL_NULL          | SQL_NULL                | SQL_NULL                | SQL_NULL                |
Line 127: Line 177:
 (3) Allowing streams (3) Allowing streams
  
-For compatibility the execute() function could be changed to PDO_PARAM_AUTO for less BC breaks.+For compatibility the execute() function could be changed to PDO_PARAM_ZVAL for less BC breaks on certain drivers.
internals/pdo/brainstorming.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

Page Tools