oci8: create compact trigger/sequence names

This enhancement provides a method of creating an emulated auto-
increment column for a table with a name greater than 25 characters,
built using createTableSql() and specifying an "AUTO" option on the
required column.

Instead of using the table name, a CRC32 value of the tablename is
created and used for the name of the sequence and trigger, i.e. instead
of a trigger called "TRIG_EMPLOYEES" for a table called "EMPLOYEES", it
creates a trigger "TRIG_3129131776", and similarly, a trigger for a
table named "EMPLOYEE_HOURLY_PAY_RATES" becomes "TRIG_3754194288". The
name of the trigger and sequence can be easily obtained after the fact
by finding the CRC32 value of the table name.

The feature is provided with a compatibility flag that must be enabled.
Existing configurations that already use this feature are unchanged. To
activate, set the dictionary class variable
`$dict->useCompactAutoIncrements = true` when building the table, and
the connection class variable
`$db->useCompactAutoIncrements = true` when using the table in ADOdb.

The feature is global for the database and cannot be specified on a
table level basis.

Fixes #565

1 files changed, 54 insertions, 0 deletions

diff --git a/drivers/adodb-oci8.inc.php b/drivers/adodb-oci8.inc.php
index 2658a3c0..12422969 100644
--- a/drivers/adodb-oci8.inc.php
+++ b/drivers/adodb-oci8.inc.php
@@ -103,6 +103,23 @@ END;
 
 	// var $ansiOuter = true; // if oracle9
 
+	/*
+	* Legacy compatibility for sequence names for emulated auto-increments
+	*/
+	public $useCompactAutoIncrements = false;
+	
+	/*
+	* Defines the schema name for emulated auto-increment columns
+	*/
+	public $schema = false;
+	
+	/*
+	* Defines the prefix for emulated auto-increment columns
+	*/
+	public $seqPrefix = 'SEQ_';
+
+
+	
 	function __construct()
 	{
 		$this->_hasOciFetchStatement = ADODB_PHPVER >= 0x4200;
@@ -304,6 +321,43 @@ END;
 	{
 		return " NVL($field, $ifNull) "; // if Oracle
 	}
+	
+	function _insertid($tabname,$column='')
+	{
+		
+		if (!$this->seqField) 
+			return false;
+
+		
+		if ($this->schema) 
+		{
+			$t = strpos($tabname,'.');
+			if ($t !== false) 
+				$tab = substr($tabname,$t+1);
+			else 
+				$tab = $tabname;
+			
+			if ($this->useCompactAutoIncrements)
+				$tab = sprintf('%u',crc32(strtolower($tab)));
+				
+			$seqname = $this->schema.'.'.$this->seqPrefix.$tab;
+		} 
+		else 
+		{
+			if ($this->useCompactAutoIncrements)
+				$tabname = sprintf('%u',crc32(strtolower($tabname)));
+			
+			$seqname = $this->seqPrefix.$tabname;
+		}
+
+		if (strlen($seqname) > 30)
+			/*
+			* We cannot successfully identify the sequence
+			*/
+			return false;
+		
+		return $this->getOne("SELECT $seqname.currval FROM dual");
+	}
 
 	// format and return date string in database date format
 	function DBDate($d,$isfld=false)