* @return mixed the normalised value
*/
private function normalise_value($column, $value) {
- if (is_bool($value)) { /// Always, convert boolean to int
+ if (is_bool($value)) { // Always, convert boolean to int
$value = (int)$value;
} else if ($column->meta_type == 'B') { // CLOB detected, we return 'blob' array instead of raw value to allow
}
/**
- * This function will handle all the records before being inserted/updated to DB for Oracle
+ * This function will handle all the column values before being inserted/updated to DB for Oracle
* installations. This is because the "special feature" of Oracle where the empty string is
* equal to NULL and this presents a problem with all our currently NOT NULL default '' fields.
- *
- * Once Moodle DB will be free of this sort of false NOT NULLS, this hack could be removed safely
+ * (and with empties handling in general)
*
* Note that this function is 100% private and should be used, exclusively by DML functions
- * in this file. Also, this is considered a DIRTY HACK to be removed when possible. (stronk7)
+ * in this file. Also, this is considered a DIRTY HACK to be removed when possible.
*
* This function is private and must not be used outside this driver at all
*
*/
private function oracle_dirty_hack ($table, $field, $value) {
- /// Get metadata
+ // Get metadata
$columns = $this->get_columns($table);
if (!isset($columns[$field])) {
return $value;
}
$column = $columns[$field];
- /// For Oracle DB, empty strings are converted to NULLs in DB
- /// and this breaks a lot of NOT NULL columns currenty Moodle. In the future it's
- /// planned to move some of them to NULL, if they must accept empty values and this
- /// piece of code will become less and less used. But, for now, we need it.
- /// What we are going to do is to examine all the data being inserted and if it's
- /// an empty string (NULL for Oracle) and the field is defined as NOT NULL, we'll modify
- /// such data in the best form possible ("0" for booleans and numbers and " " for the
- /// rest of strings. It isn't optimal, but the only way to do so.
- /// In the oppsite, when retrieving records from Oracle, we'll decode " " back to
- /// empty strings to allow everything to work properly. DIRTY HACK.
-
- /// If the field ins't VARCHAR or CLOB, skip
+ // !! This paragraph explains behaviour before Moodle 2.0:
+ //
+ // For Oracle DB, empty strings are converted to NULLs in DB
+ // and this breaks a lot of NOT NULL columns currenty Moodle. In the future it's
+ // planned to move some of them to NULL, if they must accept empty values and this
+ // piece of code will become less and less used. But, for now, we need it.
+ // What we are going to do is to examine all the data being inserted and if it's
+ // an empty string (NULL for Oracle) and the field is defined as NOT NULL, we'll modify
+ // such data in the best form possible ("0" for booleans and numbers and " " for the
+ // rest of strings. It isn't optimal, but the only way to do so.
+ // In the oppsite, when retrieving records from Oracle, we'll decode " " back to
+ // empty strings to allow everything to work properly. DIRTY HACK.
+
+ // !! These paragraphs explain the rationale about the change for Moodle 2.0:
+ //
+ // Before Moodle 2.0, we only used to apply this DIRTY HACK to NOT NULL columns, as
+ // stated above, but it causes one problem in NULL columns where both empty strings
+ // and real NULLs are stored as NULLs, being impossible to diferentiate them when
+ // being retrieved from DB.
+ //
+ // So, starting with Moodle 2.0, we are going to apply the DIRTY HACK to all the
+ // CHAR/CLOB columns no matter of their nullability. That way, when retrieving
+ // NULLABLE fields we'll get proper empties and NULLs diferentiated, so we'll be able
+ // to rely in NULL/empty/content contents without problems, until now that wasn't
+ // possible at all.
+ //
+ // No breackage with old data is expected as long as at the time of writing this
+ // (20090922) all the current uses of both sql_empty() and sql_isempty() has been
+ // revised in 2.0 and all them were being performed against NOT NULL columns,
+ // where nothing has changed (the DIRTY HACK was already being applied).
+ //
+ // !! Conclusions:
+ //
+ // From Moodle 2.0 onwards, ALL empty strings in Oracle DBs will be stored as
+ // 1-whitespace char, ALL NULLs as NULLs and, obviously, content as content. And
+ // those 1-whitespace chars will be converted back to empty strings by all the
+ // get_field/record/set() functions transparently and any SQL needing direct handling
+ // of empties will need to use the sql_empty() and sql_isempty() helper functions.
+ // MDL-17491.
+
+ // If the field ins't VARCHAR or CLOB, skip
if ($column->meta_type != 'C' and $column->meta_type != 'X') {
return $value;
}
- /// If the field isn't NOT NULL, skip (it's nullable, so accept empty-null values)
- if (!$column->not_null) {
- return $value;
- }
-
- /// If the value isn't empty, skip
+ // If the value isn't empty, skip
if (!empty($value)) {
return $value;
}
- /// Now, we have one empty value, going to be inserted to one NOT NULL, VARCHAR2 or CLOB field
- /// Try to get the best value to be inserted
+ // Now, we have one empty value, going to be inserted to one VARCHAR2 or CLOB field
+ // Try to get the best value to be inserted
- /// The '0' string doesn't need any transformation, skip
+ // The '0' string doesn't need any transformation, skip
if ($value === '0') {
return $value;
}
- /// Transformations start
+ // Transformations start
if (gettype($value) == 'boolean') {
- return '0'; /// Transform false to '0' that evaluates the same for PHP
+ return '0'; // Transform false to '0' that evaluates the same for PHP
} else if (gettype($value) == 'integer') {
- return '0'; /// Transform 0 to '0' that evaluates the same for PHP
-
- } else if (gettype($value) == 'NULL') {
- return '0'; /// Transform NULL to '0' that evaluates the same for PHP
+ return '0'; // Transform 0 to '0' that evaluates the same for PHP
} else if ($value === '') {
- return ' '; /// Transform '' to ' ' that DONT'T EVALUATE THE SAME
- /// (we'll transform back again on get_records_XXX functions and others)!!
+ return ' '; // Transform '' to ' ' that DONT'T EVALUATE THE SAME
+ // (we'll transform back again on get_records_XXX functions and others)!!
}
- /// Fail safe to original value
+ // Fail safe to original value
return $value;
}
if (isset($value['clob'])) {
$lob = oci_new_descriptor($this->oci, OCI_DTYPE_LOB);
oci_bind_by_name($stmt, $key, $lob, -1, SQLT_CLOB);
- $lob->writeTemporary($params[$key]['clob'], OCI_TEMP_CLOB);
+ $lob->writeTemporary($this->oracle_dirty_hack($tablename, $key, $params[$key]['clob']), OCI_TEMP_CLOB);
$descriptors[] = $lob;
continue; // Column binding finished, go to next one
} else if (isset($value['blob'])) {
if (strlen($value) > 4000) {
// TODO: Shouldn't arrive here ever! BIG Clobs already bound above. Exception!
}
- default: // Bind as CHAR
- oci_bind_by_name($stmt, $key, $params[$key]);
+ default: // Bind as CHAR (applying dirty hack)
+ oci_bind_by_name($stmt, $key, $this->oracle_dirty_hack($tablename, $key, $params[$key]));
}
}
}
}
public function sql_isempty($tablename, $fieldname, $nullablefield, $textfield) {
- if ($nullablefield) {
- return " $fieldname IS NULL "; /// empties in nullable fields are stored as
- } else { /// NULLs
- if ($textfield) {
- return " ".$this->sql_compare_text($fieldname)." = ' ' "; /// oracle_dirty_hack inserts 1-whitespace
- } else { /// in NOT NULL varchar and text columns so
- return " $fieldname = ' ' "; /// we need to look for that in any situation
- }
+ if ($textfield) {
+ return " ".$this->sql_compare_text($fieldname)." = '".$this->sql_empty()."' ";
+ } else {
+ return " $fieldname = '".$this->sql_empty()."' ";
}
}
return ' ';
}
+ public function sql_order_by_text($fieldname, $numchars=32) {
+ return 'dbms_lob.substr(' . $fieldname . ', ' . $numchars . ',1)';
+ }
+
/// session locking
// http://download.oracle.com/docs/cd/B10501_01/appdev.920/a96612/d_lock2.htm#999576
if (!parent::begin_sql()) {
return false;
}
- return true;
-
- $sql = "BEGIN";
- $this->query_start($sql, NULL, SQL_QUERY_AUX);
- $stmt = $this->parse_query($sql);
- $result = oci_execute($stmt, $this->commit_status);
- $this->query_end($result, $stmt);
- oci_free_statement($stmt);
+ $this->commit_status = OCI_DEFAULT; //Done! ;-)
return true;
}
if (!parent::commit_sql()) {
return false;
}
- return true;
- $sql = "COMMIT";
- $this->query_start($sql, NULL, SQL_QUERY_AUX);
- $stmt = $this->parse_query($sql);
- $result = oci_execute($stmt, $this->commit_status);
- $this->query_end($result, $stmt);
- oci_free_statement($stmt);
+ $this->query_start('--oracle_commit', NULL, SQL_QUERY_AUX);
+ $result = oci_commit($this->oci);
+ $this->commit_status = OCI_COMMIT_ON_SUCCESS;
+ $this->query_end($result);
return true;
}
if (!parent::rollback_sql()) {
return false;
}
- return true;
- $sql = "ROLLBACK";
- $this->query_start($sql, NULL, SQL_QUERY_AUX);
- $stmt = $this->parse_query($sql);
- $result = oci_execute($stmt, $this->commit_status);
- $this->query_end($result, $stmt);
- oci_free_statement($stmt);
+ $this->query_start('--oracle_rollback', NULL, SQL_QUERY_AUX);
+ $result = oci_rollback($this->oci);
+ $this->commit_status = OCI_COMMIT_ON_SUCCESS;
+ $this->query_end($result);
return true;
}
}
projects / moodle.git / commitdiff