A fix and a test case for Bug#25859 ALTER DATABASE works w/o parameters.

Fix the parser to make the database options not optional.

mysql-test/r/information_schema.result

@@ -1013,7 +1013,7 @@ c	int(11)	YES		NULL
 drop view v1;
 drop table t1;
 alter database information_schema;
-ERROR 42000: Access denied for user 'root'@'localhost' to database 'information_schema'
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
 drop database information_schema;
 ERROR 42000: Access denied for user 'root'@'localhost' to database 'information_schema'
 drop table information_schema.tables;
@@ -1326,3 +1326,8 @@ v2	YES
 delete from v1;
 drop view v1,v2;
 drop table t1,t2;
+alter database;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
+alter database test;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
+End of 5.0 tests.

mysql-test/t/information_schema.test

@@ -697,7 +697,7 @@ drop table t1;
 #
 # Bug #9846 Inappropriate error displayed while dropping table from 'INFORMATION_SCHEMA'
 #
---error 1044
+--error ER_PARSE_ERROR
 alter database information_schema;
 --error 1044
 drop database information_schema;
@@ -1038,4 +1038,11 @@ delete from v1;
 drop view v1,v2;
 drop table t1,t2;
 
-# End of 5.0 tests.
+#
+# Bug#25859    ALTER DATABASE works w/o parameters
+#
+--error ER_PARSE_ERROR
+alter database;
+--error ER_PARSE_ERROR
+alter database test;
+--echo End of 5.0 tests.

sql/sql_yacc.yy

@@ -3621,7 +3621,7 @@ alter:
             Lex->create_info.default_table_charset= NULL;
             Lex->create_info.used_fields= 0;
           }
-          opt_create_database_options
+          create_database_options
 	  {
 	    LEX *lex=Lex;
 	    lex->sql_command=SQLCOM_ALTER_DB;