Syntax extention: 'ALTER DATABASE' without db name (after review)

mysql-test/r/ctype_create.result

@@ -63,3 +63,12 @@ ERROR HY000: Conflicting declarations: 'CHARACTER SET latin1' and 'CHARACTER SET
 create database d1 default character set latin1 collate latin2_bin;
 ERROR 42000: COLLATION 'latin2_bin' is not valid for CHARACTER SET 'latin1'
 DROP DATABASE mysqltest1;
+CREATE DATABASE mysqltest2 DEFAULT CHARACTER SET latin7;
+use mysqltest2;
+ALTER DATABASE DEFAULT CHARACTER SET latin2;
+show create database mysqltest2;
+Database	Create Database
+mysqltest2	CREATE DATABASE `mysqltest2` /*!40100 DEFAULT CHARACTER SET latin2 */
+drop database mysqltest2;
+ALTER DATABASE DEFAULT CHARACTER SET latin2;
+ERROR 3D000: No database selected

mysql-test/t/ctype_create.test

@@ -86,3 +86,15 @@ create database d1 default character set latin1 collate latin2_bin;
 #
 #
 DROP DATABASE mysqltest1;
+
+
+#
+# Synatx: 'ALTER DATABASE' without db_name
+#
+CREATE DATABASE mysqltest2 DEFAULT CHARACTER SET latin7;
+use mysqltest2;
+ALTER DATABASE DEFAULT CHARACTER SET latin2;
+show create database mysqltest2;
+drop database mysqltest2;
+--error 1046
+ALTER DATABASE DEFAULT CHARACTER SET latin2;

sql/sql_parse.cc

@@ -3184,9 +3184,15 @@ purposes internal to the MySQL server", MYF(0));
   }
   case SQLCOM_ALTER_DB:
   {
-    if (!strip_sp(lex->name) || check_db_name(lex->name))
+    char *db= lex->name ? lex->name : thd->db;
+    if (!db)
     {
-      net_printf(thd, ER_WRONG_DB_NAME, lex->name);
+      send_error(thd, ER_NO_DB_ERROR);
+      goto error;
+    }
+    if (!strip_sp(db) || check_db_name(db))
+    {
+      net_printf(thd, ER_WRONG_DB_NAME, db);
       break;
     }
     /*
@@ -3198,21 +3204,21 @@ purposes internal to the MySQL server", MYF(0));
     */
 #ifdef HAVE_REPLICATION
     if (thd->slave_thread && 
-	(!db_ok(lex->name, replicate_do_db, replicate_ignore_db) ||
-	 !db_ok_with_wild_table(lex->name)))
+	(!db_ok(db, replicate_do_db, replicate_ignore_db) ||
+	 !db_ok_with_wild_table(db)))
     {
       my_error(ER_SLAVE_IGNORED_TABLE, MYF(0));
       break;
     }
 #endif
-    if (check_access(thd,ALTER_ACL,lex->name,0,1,0))
+    if (check_access(thd, ALTER_ACL, db, 0, 1, 0))
       break;
     if (thd->locked_tables || thd->active_transaction())
     {
       send_error(thd,ER_LOCK_OR_ACTIVE_TRANSACTION);
       goto error;
     }
-    res=mysql_alter_db(thd,lex->name,&lex->create_info);
+    res= mysql_alter_db(thd, db, &lex->create_info);
     break;
   }
   case SQLCOM_SHOW_CREATE_DB:

sql/sql_yacc.yy

@@ -609,7 +609,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 
 %type <simple_string>
 	remember_name remember_end opt_ident opt_db text_or_password
-	opt_constraint constraint
+	opt_constraint constraint ident_or_empty
 
 %type <string>
 	text_string opt_gconcat_separator
@@ -1870,7 +1870,7 @@ alter:
 	}
 	alter_list
 	{}
-	| ALTER DATABASE ident
+	| ALTER DATABASE ident_or_empty
           {
             Lex->create_info.default_table_charset= NULL;
             Lex->create_info.used_fields= 0;
@@ -1879,10 +1879,15 @@ alter:
 	  {
 	    LEX *lex=Lex;
 	    lex->sql_command=SQLCOM_ALTER_DB;
-	    lex->name=$3.str;
+	    lex->name= $3;
 	  };
 
 
+ident_or_empty:
+	/* empty */  { $$= 0; }
+	| ident      { $$= $1.str; };
+
+
 alter_list:
 	| DISCARD TABLESPACE { Lex->alter_info.tablespace_op= DISCARD_TABLESPACE; }
 	| IMPORT TABLESPACE { Lex->alter_info.tablespace_op= IMPORT_TABLESPACE; }