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, 43 insertions, 16 deletions

diff --git a/datadict/datadict-oci8.inc.php b/datadict/datadict-oci8.inc.php
index de76392b..7054e4bb 100644
--- a/datadict/datadict-oci8.inc.php
+++ b/datadict/datadict-oci8.inc.php
@@ -25,8 +25,15 @@ class ADODB2_oci8 extends ADODB_DataDict {
 	var $alterCol = ' MODIFY ';
 	var $typeX = 'VARCHAR(4000)';
 	var $typeXL = 'CLOB';
+	
+	/*
+	* Legacy compatibility for sequence names for emulated auto-increments
+	* If set to true, creates sequences and triggers as TRIG_394545594
+	* instead of TRIG_possibly_too_long_tablename
+	*/
+	public $useCompactAutoIncrements = false;
 
-	function MetaType($t, $len=-1, $fieldobj=false)
+	function metaType($t, $len=-1, $fieldobj=false)
 	{
 		if (is_object($t)) {
 			$fieldobj = $t;
@@ -185,32 +192,52 @@ class ADODB2_oci8 extends ADODB_DataDict {
 		return $suffix;
 	}
 
-/*
-CREATE or replace TRIGGER jaddress_insert
-before insert on jaddress
-for each row
-begin
-select seqaddress.nextval into :new.A_ID from dual;
-end;
-*/
+	/**
+	* Creates an insert trigger to emulate an auto-increment column
+	* in a table
+	*
+	* @param	str		$tabname		The name of the table
+	* @param	str[]	$tableoptions   Optional configuration items
+	*
+	* @return	str[]	The SQL statements to create the trigger
+	*/
 	function _Triggers($tabname,$tableoptions)
 	{
+		
 		if (!$this->seqField) return array();
 
-		if ($this->schema) {
+		if ($this->schema) 
+		{
 			$t = strpos($tabname,'.');
-			if ($t !== false) $tab = substr($tabname,$t+1);
-			else $tab = $tabname;
+			if ($t !== false) 
+				$tab = substr($tabname,$t+1);
+			else 
+				$tab = $tabname;
+			
+			if ($this->connection->useCompactAutoIncrements)
+				$id = sprintf('%u',crc32(strtolower($tab)));
+			else
+				$id = $tab;
+			
 			$seqname = $this->schema.'.'.$this->seqPrefix.$tab;
 			$trigname = $this->schema.'.'.$this->trigPrefix.$this->seqPrefix.$tab;
-		} else {
-			$seqname = $this->seqPrefix.$tabname;
-			$trigname = $this->trigPrefix.$seqname;
+			
+		} 
+		else 
+		{
+			if ($this->connection->useCompactAutoIncrements)
+				$id = sprintf('%u',crc32(strtolower($tabname)));
+			else
+				$id = $tabname;
+			
+			$seqname = $this->seqPrefix.$id;
+			$trigname = $this->trigPrefix.$id;
 		}
 
 		if (strlen($seqname) > 30) {
 			$seqname = $this->seqPrefix.uniqid('');
 		} // end if
+		
 		if (strlen($trigname) > 30) {
 			$trigname = $this->trigPrefix.uniqid('');
 		} // end if
@@ -222,7 +249,7 @@ end;
 		if (isset($tableoptions['SEQUENCE_INCREMENT'])){$seqIncr = ' INCREMENT BY '.$tableoptions['SEQUENCE_INCREMENT'];}
 		$seqStart = '';
 		if (isset($tableoptions['SEQUENCE_START'])){$seqStart = ' START WITH '.$tableoptions['SEQUENCE_START'];}
-		$sql[] = "CREATE SEQUENCE $seqname $seqStart $seqIncr $seqCache";
+		$sql[] = "CREATE SEQUENCE $seqname MINVALUE 1 $seqStart $seqIncr $seqCache";
 		$sql[] = "CREATE OR REPLACE TRIGGER $trigname BEFORE insert ON $tabname FOR EACH ROW WHEN (NEW.$this->seqField IS NULL OR NEW.$this->seqField = 0) BEGIN select $seqname.nextval into :new.$this->seqField from dual; END;";
 
 		$this->seqField = false;