MySQL 8: fix duplicates in foreign keys

Former-commit-id: 01ee975c

plugins/org.jkiss.dbeaver.ext.mysql/src/org/jkiss/dbeaver/ext/mysql/model/MySQLTable.java

@@ -494,7 +494,14 @@ public class MySQLTable extends MySQLTableBase implements DBPObjectStatistics
                             fkList.add(fk);
                         }
                         MySQLTableForeignKeyColumn fkColumnInfo = new MySQLTableForeignKeyColumn(fk, fkColumn, keySeq, pkColumn);
-                        fk.addColumn(fkColumnInfo);
+                        if (fk.hasColumn(fkColumnInfo)) {
+                            // Known MySQL bug, metaData.getImportedKeys() can return duplicates
+                            // https://bugs.mysql.com/bug.php?id=95280
+                            log.debug("FK "+ fkName +" has already been added, skip");
+                        }
+                        else {
+                            fk.addColumn(fkColumnInfo);
+                        }
                     }
                 }
             } finally {

plugins/org.jkiss.dbeaver.ext.mysql/src/org/jkiss/dbeaver/ext/mysql/model/MySQLTableForeignKey.java

@@ -89,6 +89,20 @@ public class MySQLTableForeignKey extends JDBCTableForeignKey<MySQLTable, MySQLT
         columns.add(column);
     }
 
+    public boolean hasColumn(MySQLTableForeignKeyColumn column) {
+        if (columns != null) {
+            String columnName = column.getName();
+            String refName = column.getReferencedColumn().getName();
+            for (MySQLTableForeignKeyColumn col : columns) {
+                if (columnName.equals(col.getName()) &&
+                    refName.equals(col.getReferencedColumn().getName())) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
     @NotNull
     @Override
     public String getFullyQualifiedName(DBPEvaluationContext context)