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MDL-17491 oci native driver: preparing to support transactions, oracle dirty hack and others. WIP

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This commit is contained in:
stronk7
2009-09-21 11:28:42 +00:00
parent 849185cee9
commit 8089f8f67e
1 changed files with 126 additions and 38 deletions
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lib/dml/oci_native_moodle_database.php
+126 -38
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@@ -30,13 +30,17 @@ require_once($CFG->libdir.'/dml/oci_native_moodle_recordset.php');
/**
* Native oci class representing moodle database interface.
*
* One complete reference for PHP + OCI:
* http://www.oracle.com/technology/tech/php/underground-php-oracle-manual.html
*/
class oci_native_moodle_database extends moodle_database {
protected $oci = null;
protected $bytea_oid = null;
private $last_stmt_error = null; // To store stmt errors and enable get_last_error() to detect them
private $commit_status = OCI_COMMIT_ON_SUCCESS; // Autocommit ON by default. Switching to OFF (OCI_DEFAULT)
// when playing with transactions
/**
* Detects if all needed PHP stuff installed.
@@ -149,9 +153,9 @@ class oci_native_moodle_database extends moodle_database {
ob_start();
if (empty($this->dboptions['dbpersit'])) {
$this->oci = oci_connect($this->dbuser, $this->dbpass, $this->dbname, 'UTF-8');
$this->oci = oci_connect($this->dbuser, $this->dbpass, $this->dbname, 'AL32UTF8');
} else {
$this->oci = oci_pconnect($this->dbuser, $this->dbpass, $this->dbname, 'UTF-8');
$this->oci = oci_pconnect($this->dbuser, $this->dbpass, $this->dbname, 'AL32UTF8');
}
$dberr = ob_get_contents();
ob_end_clean();
@@ -269,7 +273,7 @@ class oci_native_moodle_database extends moodle_database {
protected function parse_query($sql) {
$stmt = oci_parse($this->oci, $sql);
if ($stmt === false) {
if ($stmt == false) {
throw new dml_connection_exception('Can not parse sql query'); //TODO: maybe add better info
}
return $stmt;
@@ -289,7 +293,8 @@ class oci_native_moodle_database extends moodle_database {
AND TABLE_NAME LIKE '$prefix%' ESCAPE '\\'";
$this->query_start($sql, null, SQL_QUERY_AUX);
$stmt = $this->parse_query($sql);
$result = oci_execute($stmt);
oci_num_fields($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
$records = null;
oci_fetch_all($stmt, $records, 0, -1, OCI_ASSOC);
@@ -322,7 +327,7 @@ class oci_native_moodle_database extends moodle_database {
ORDER BY i.INDEX_NAME, c.COLUMN_POSITION";
$stmt = $this->parse_query($sql);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
$records = null;
oci_fetch_all($stmt, $records, 0, -1, OCI_FETCHSTATEMENT_BY_ROW);
@@ -367,7 +372,7 @@ class oci_native_moodle_database extends moodle_database {
$this->query_start($sql, null, SQL_QUERY_AUX);
$stmt = $this->parse_query($sql);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
$records = null;
oci_fetch_all($stmt, $records, 0, -1, OCI_FETCHSTATEMENT_BY_ROW);
@@ -534,6 +539,84 @@ class oci_native_moodle_database extends moodle_database {
return $this->columns[$table];
}
/**
* This function will handle all the records 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
*
* 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)
*
* This function is private and must not be used outside this driver at all
*
* @param $table string the table where the record is going to be inserted/updated (without prefix)
* @param $field string the field where the record is going to be inserted/updated
* @param $value mixed the value to be inserted/updated
*/
private function oracle_dirty_hack ($table, $field, $value) {
/// 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
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 $value;
}
/// If the value isn't empty, skip
if (!empty($value)) {
return $value;
}
/// Now, we have one empty value, going to be inserted to one NOT NULL, VARCHAR2 or CLOB field
/// Try to get the best value to be inserted
/// The '0' string doesn't need any transformation, skip
if ($value === '0') {
return $value;
}
/// Transformations start
if (gettype($value) == 'boolean') {
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
} else if ($value === '') {
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
return $value;
}
/**
* Is db in unicode mode?
* @return bool
@@ -544,7 +627,7 @@ class oci_native_moodle_database extends moodle_database {
WHERE PARAMETER = 'NLS_CHARACTERSET'";
$this->query_start($sql, null, SQL_QUERY_AUX);
$stmt = $this->parse_query($sql);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
$records = null;
oci_fetch_all($stmt, $records, 0, -1, OCI_FETCHSTATEMENT_BY_COLUMN);
@@ -564,14 +647,14 @@ class oci_native_moodle_database extends moodle_database {
$this->query_start($sql, null, SQL_QUERY_STRUCTURE);
$stmt = $this->parse_query($sql);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
oci_free_statement($stmt);
return true;
}
protected function bind_params($stmt, array $params=null, $tablename=null) {
protected function bind_params(&$stmt, array $params=null, $tablename=null) {
$descriptors = array();
if ($params) {
$columns = array();
@@ -656,7 +739,7 @@ class oci_native_moodle_database extends moodle_database {
$this->query_start($sql, $params, SQL_QUERY_UPDATE);
$stmt = $this->parse_query($sql);
$this->bind_params($stmt, $params);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
oci_free_statement($stmt);
@@ -719,33 +802,36 @@ class oci_native_moodle_database extends moodle_database {
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
if ($limitfrom and $limitnum) {
$sql = "SELECT oracle_o.*
FROM (SELECT oracle_i.*, rownum AS oracle_rownum
FROM ($sql) oracle_i
) oracle_o
WHERE rownum <= :oracle_max AND oracle_rownum > :oracle_min";
$rawsql = "SELECT oracle_o.*
FROM (SELECT oracle_i.*, rownum AS oracle_rownum
FROM ($sql) oracle_i
) oracle_o
WHERE rownum <= :oracle_max AND oracle_rownum > :oracle_min";
$params['oracle_max'] = $limitfrom + $limitnum;
$params['oracle_min'] = $limitfrom;
} else if ($limitfrom and !$limitnum) {
$sql = "SELECT oracle_o.*
FROM (SELECT oracle_i.*, rownum AS oracle_rownum
FROM ($sql) oracle_i
) oracle_o
WHERE oracle_rownum > :oracle_min";
$rawsql = "SELECT oracle_o.*
FROM (SELECT oracle_i.*, rownum AS oracle_rownum
FROM ($sql) oracle_i
) oracle_o
WHERE oracle_rownum > :oracle_min";
$params['oracle_min'] = $limitfrom;
} else if (!$limitfrom and $limitnum) {
$sql = "SELECT *
FROM ($sql)
WHERE rownum <= :oracle_max";
$rawsql = "SELECT *
FROM ($sql)
WHERE rownum <= :oracle_max";
$params['oracle_max'] = $limitnum;
} else { // No limitfrom nor limitnum
$rawsql = $sql;
}
$this->query_start($sql, $params, SQL_QUERY_SELECT);
$stmt = $this->parse_query($sql);
$stmt = $this->parse_query($rawsql);
$this->bind_params($stmt, $params);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
return $this->create_recordset($stmt);
@@ -804,7 +890,7 @@ class oci_native_moodle_database extends moodle_database {
$this->query_start($sql, $params, SQL_QUERY_SELECT);
$stmt = $this->parse_query($sql);
$this->bind_params($stmt, $params);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
$records = null;
@@ -842,7 +928,7 @@ class oci_native_moodle_database extends moodle_database {
$this->query_start($sql, $params, SQL_QUERY_SELECT);
$stmt = $this->parse_query($sql);
$this->bind_params($stmt, $params);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
$records = null;
@@ -904,7 +990,7 @@ class oci_native_moodle_database extends moodle_database {
if ($returning) {
oci_bind_by_name($stmt, ":oracle_id", $id, -1, SQLT_LNG);
}
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->free_descriptors($descriptors);
$this->query_end($result, $stmt);
oci_free_statement($stmt);
@@ -937,10 +1023,12 @@ class oci_native_moodle_database extends moodle_database {
$dataobject = (object)$dataobject;
}
$columns = $this->get_columns($table);
unset($dataobject->id);
$columns = $this->get_columns($table);
$cleaned = array();
$blobs = array();
$clobs = array();
foreach ($dataobject as $field=>$value) {
if (!isset($columns[$field])) {
@@ -1014,7 +1102,7 @@ class oci_native_moodle_database extends moodle_database {
$this->query_start($sql, $params, SQL_QUERY_UPDATE);
$stmt = $this->parse_query($sql);
$descriptors = $this->bind_params($stmt, $params, $table);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
$this->free_descriptors($descriptors);
oci_free_statement($stmt);
@@ -1088,7 +1176,7 @@ class oci_native_moodle_database extends moodle_database {
$this->query_start($sql, $params, SQL_QUERY_UPDATE);
$stmt = $this->parse_query($sql);
$descriptors = $this->bind_params($stmt, $params, $table);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
$this->free_descriptors($descriptors);
oci_free_statement($stmt);
@@ -1116,7 +1204,7 @@ class oci_native_moodle_database extends moodle_database {
$this->query_start($sql, $params, SQL_QUERY_UPDATE);
$stmt = $this->parse_query($sql);
$this->bind_params($stmt, $params);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
oci_free_statement($stmt);
@@ -1207,7 +1295,7 @@ class oci_native_moodle_database extends moodle_database {
}
}
function sql_empty() {
public function sql_empty() {
return ' ';
}
@@ -1230,7 +1318,7 @@ class oci_native_moodle_database extends moodle_database {
$sql = "BEGIN";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$stmt = $this->parse_query($sql);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
oci_free_statement($stmt);
return true;
@@ -1248,7 +1336,7 @@ class oci_native_moodle_database extends moodle_database {
$sql = "COMMIT";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$stmt = $this->parse_query($sql);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
oci_free_statement($stmt);
return true;
@@ -1266,7 +1354,7 @@ class oci_native_moodle_database extends moodle_database {
$sql = "ROLLBACK";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$stmt = $this->parse_query($sql);
$result = oci_execute($stmt);
$result = oci_execute($stmt, $this->commit_status);
$this->query_end($result, $stmt);
oci_free_statement($stmt);
return true;