Syntax recognize drop database

lib/myparser.y

@@ -114,6 +114,7 @@ cmdx ::= select_stmt.
 cmdx ::= update_stmt.
 cmdx ::= delete_stmt.
 cmdx ::= insert_stmt.
+cmdx ::= drop_database_stmt.
 
 ///////////////////// EXPLAIN syntax ////////////////////////////
 cmd ::= explain fullname(X) opt_col_name. {
@@ -424,7 +425,6 @@ ddl_cmd_head ::= DROP VIEW.
 
 %token_class db_schema DATABASE|SCHEMA.
 ddl_cmd_head ::= CREATE db_schema.
-ddl_cmd_head ::= DROP db_schema.
 ddl_cmd_head ::= ALTER db_schema.
 
 ddl_cmd_head ::= CREATE TABLE.
@@ -435,6 +435,19 @@ ddl_cmd_head ::= ALTER TABLE.
 opt_unique ::= UNIQUE.
 opt_unique ::= .
 
+////////////////////////// The DROP DATABASE /////////////////////////////////////
+//
+drop_database_stmt ::= DROP db_schema ifexists(A) nm(B). {
+    sql_drop_database_t *p = sql_drop_database_new();
+    sql_drop_database(context, p);
+    p->schema_name = sql_token_dup(B);
+    p->ifexists = A;
+}
+
+%type ifexists {int}
+ifexists(A) ::= IF EXISTS.   {A = 1;}
+ifexists(A) ::= .            {A = 0;}
+
 //////////////////////// The SELECT statement /////////////////////////////////
 //
 select_stmt ::= select(X).  {

lib/simple-parser.y

@@ -421,6 +421,17 @@ cmd ::= DROP TABLE ifexists nm. {
 ifexists(A) ::= IF EXISTS.   {A = 1;}
 ifexists(A) ::= .            {A = 0;}
 
+////////////////////////// The DROP DATABASE /////////////////////////////////////
+//
+%token_class db_schema DATABASE|SCHEMA.
+
+cmd ::= DROP db_schema ifexists(A) nm(B). {
+    sql_drop_database_t *p = sql_drop_database_new();
+    sql_drop_database(context, p);
+    p->schema_name = sql_token_dup(B);
+    p->ifexists = A;
+}
+
 //////////////////////// ALTER TABLE //////////////////////////////////
 cmd ::= ALTER TABLE. {
     context->rw_flag |= CF_WRITE;

lib/sql-expression.c

@@ -672,6 +672,23 @@ sql_src_item_free(void *p)
     g_free(item);
 }
 
+sql_drop_database_t *
+sql_drop_database_new()
+{
+    sql_drop_database_t *p = g_new0(sql_drop_database_t, 1);
+    return p;
+}
+
+void
+sql_drop_database_free(sql_drop_database_t *p)
+{
+    if(!p) return;
+    if(p && p->schema_name) {
+        g_free(p->schema_name);
+    }
+    g_free(p);
+}
+
 sql_src_list_t *
 sql_src_list_append(sql_src_list_t *p, sql_token_t *tname,
                     sql_token_t *dbname, sql_token_t *alias, sql_select_t *subquery,

lib/sql-expression.h

@@ -59,6 +59,7 @@ typedef struct sql_insert_t sql_insert_t;
 typedef enum sql_stmt_type_t sql_stmt_type_t;
 typedef struct sql_column_t sql_column_t;
 typedef GPtrArray sql_column_list_t;
+typedef struct sql_drop_database_t sql_drop_database_t;
 
 enum sql_stmt_type_t {
     STMT_UNKOWN,
@@ -83,6 +84,8 @@ enum sql_stmt_type_t {
     STMT_SHOW_COLUMNS,
     STMT_SHOW_CREATE,
     STMT_SHOW_WARNINGS,
+
+    STMT_DROP_DATABASE,
 };
 struct sql_token_t {
     char *z;              /* pointer to token text, not NUL-terminated */
@@ -243,6 +246,11 @@ struct sql_src_item_t {
     sql_expr_list_t *func_arg;  /* Arguments to table-valued-function */
 };                              /* One entry for each identifier on the list */
 
+struct sql_drop_database_t {
+    char *schema_name;
+    uint8_t ifexists;
+};
+
 typedef struct sql_set_transaction_t {
     enum sql_var_scope_t scope;
     enum sql_trx_feature_t rw_feature;
@@ -331,6 +339,9 @@ sql_column_t *sql_column_new();
 
 void sql_column_free(void *);
 
+sql_drop_database_t *sql_drop_database_new();
+void sql_drop_database_free(sql_drop_database_t *);
+
 int sql_join_type(sql_token_t kw);
 
 void sql_statement_free(void *clause, sql_stmt_type_t stmt_type);

lib/sql-operation.c

@@ -106,6 +106,13 @@ sql_savepoint(sql_context_t *st, int tk, char *name)
     sql_context_add_stmt(st, STMT_SAVEPOINT, name);
 }
 
+void
+sql_drop_database(sql_context_t *st, sql_drop_database_t *drop_database)
+{
+    st->rw_flag |= CF_WRITE;
+    sql_context_add_stmt(st, STMT_DROP_DATABASE, drop_database);
+}
+
 static gboolean
 string_array_contains(const char **sa, int size, const char *str)
 {