Author: pcl
Date: Tue Jan 2 19:02:45 2007
New Revision: 492032
URL: http://svn.apache.org/viewvc?view=rev&rev=492032
Log:
deleteTableContents optimization for MySQL. This is disabled by default, as
MySQL may fail if using InnoDB + delete constraints.
Modified:
incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
Modified:
incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
URL:
http://svn.apache.org/viewvc/incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java?view=diff&rev=492032&r1=492031&r2=492032
==============================================================================
---
incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
(original)
+++
incubator/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/sql/MySQLDictionary.java
Tue Jan 2 19:02:45 2007
@@ -50,6 +50,15 @@
*/
public boolean driverDeserializesBlobs = true;
+ /**
+ * Whether to inline multi-table bulk-delete operations into MySQL's
+ * combined <code>DELETE FROM foo, bar, baz</code> syntax.
+ * Defaults to false, since this may fail in the presence of InnoDB tables
+ * with foreign keys.
+ * @see http://dev.mysql.com/doc/refman/5.0/en/delete.html
+ */
+ public boolean optimizeMultiTableDeletes = false;
+
public MySQLDictionary() {
platform = "MySQL";
validationSQL = "SELECT NOW()";
@@ -129,6 +138,22 @@
if (fk.getColumns().length > 1)
return null;
return super.getForeignKeyConstraintSQL(fk);
+ }
+
+ public String[] getDeleteTableContentsSQL(Table[] tables) {
+ // mysql >= 4 supports more-optimal delete syntax
+ if (!optimizeMultiTableDeletes)
+ return super.getDeleteTableContentsSQL(tables);
+ else {
+ StringBuffer buf = new StringBuffer(tables.length * 8);
+ buf.append("DELETE FROM ");
+ for (int i = 0; i < tables.length; i++) {
+ buf.append(tables[i].getFullName());
+ if (i < tables.length - 1)
+ buf.append(", ");
+ }
+ return new String[] { buf.toString() };
+ }
}
protected void appendSelectRange(SQLBuffer buf, long start, long end) {
