drop table implement

src/observer/sql/executor/command_executor.cpp

@@ -17,6 +17,7 @@ See the Mulan PSL v2 for more details. */
 #include "sql/stmt/stmt.h"
 #include "sql/executor/create_index_executor.h"
 #include "sql/executor/create_table_executor.h"
+#include "sql/executor/drop_table_executor.h"
 #include "sql/executor/desc_table_executor.h"
 #include "sql/executor/help_executor.h"
 #include "sql/executor/show_tables_executor.h"
@@ -41,6 +42,11 @@ RC CommandExecutor::execute(SQLStageEvent *sql_event)
       return executor.execute(sql_event);
     } break;
 
+    case StmtType::DROP_TABLE:{
+      DropTableExecutor executor;
+      return executor.execute(sql_event);
+    } break;
+
     case StmtType::DESC_TABLE: {
       DescTableExecutor executor;
       return executor.execute(sql_event);

src/observer/sql/executor/drop_table_executor.cpp

@@ -0,0 +1,22 @@
+#include "sql/executor/drop_table_executor.h"
+
+#include "session/session.h"
+#include "common/log/log.h"
+#include "storage/table/table.h"
+#include "sql/stmt/drop_table_stmt.h"
+#include "event/sql_event.h"
+#include "event/session_event.h"
+#include "storage/db/db.h"
+
+RC DropTableExecutor::execute(SQLStageEvent *sql_event)
+{
+  Stmt *stmt = sql_event->stmt();
+  Session *session = sql_event->session_event()->session();
+  ASSERT(stmt->type() == StmtType::DROP_TABLE, 
+         "drop table executor can not run this command: %d", static_cast<int>(stmt->type()));
+
+  DropTableStmt *drop_table_stmt = static_cast<DropTableStmt *>(stmt);
+  const char *table_name = drop_table_stmt->table_name().c_str();
+  RC rc = session->get_current_db()->drop_table(table_name);
+  return rc;
+}

src/observer/sql/executor/drop_table_executor.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "common/rc.h"
+
+class SQLStageEvent;
+
+/**
+ * @brief 删除表的执行器
+ * @ingroup Executor
+ */
+class DropTableExecutor
+{
+public:
+  DropTableExecutor() = default;
+  virtual ~DropTableExecutor() = default;
+
+  RC execute(SQLStageEvent *sql_event);
+};

src/observer/sql/stmt/drop_table_stmt.cpp

@@ -0,0 +1,9 @@
+#include "sql/stmt/drop_table_stmt.h"
+#include "event/sql_debug.h"
+
+RC DropTableStmt::create(Db *db, const DropTableSqlNode &drop_table, Stmt *&stmt)
+{
+  stmt = new DropTableStmt(drop_table.relation_name);
+  sql_debug("drop table statement: table name %s", drop_table.relation_name.c_str());
+  return RC::SUCCESS;
+}

src/observer/sql/stmt/drop_table_stmt.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "sql/stmt/stmt.h"
+
+class Db;
+
+/**
+ * @brief 表示删除表的语句
+ * @ingroup Statement
+ * @details 
+ */
+class DropTableStmt : public Stmt
+{
+public:
+  DropTableStmt(const std::string &table_name)
+        : table_name_(table_name)
+  {}
+  virtual ~DropTableStmt() = default;
+
+  StmtType type() const override { return StmtType::DROP_TABLE; }
+
+  const std::string &table_name() const { return table_name_; }
+
+  static RC create(Db *db, const DropTableSqlNode &drop_table, Stmt *&stmt);
+
+private:
+  std::string table_name_;
+};

src/observer/sql/stmt/stmt.cpp

@@ -18,6 +18,7 @@ See the Mulan PSL v2 for more details. */
 #include "sql/stmt/delete_stmt.h"
 #include "sql/stmt/select_stmt.h"
 #include "sql/stmt/explain_stmt.h"
+#include "sql/stmt/drop_table_stmt.h"
 #include "sql/stmt/create_index_stmt.h"
 #include "sql/stmt/create_table_stmt.h"
 #include "sql/stmt/desc_table_stmt.h"
@@ -57,6 +58,10 @@ RC Stmt::create_stmt(Db *db, ParsedSqlNode &sql_node, Stmt *&stmt)
       return CreateTableStmt::create(db, sql_node.create_table, stmt);
     }
 
+    case SCF_DROP_TABLE:{
+      return DropTableStmt::create(db,sql_node.drop_table,stmt);
+    }
+
     case SCF_DESC_TABLE: {
       return DescTableStmt::create(db, sql_node.desc_table, stmt);
     }

src/observer/storage/db/db.cpp

@@ -101,6 +101,30 @@ RC Db::create_table(const char *table_name, int attribute_count, const AttrInfoS
   return RC::SUCCESS;
 }
 
+RC Db::drop_table(const char *table_name){
+  RC rc = RC::SUCCESS;
+  // check table_name
+  Table *table = find_table(table_name);
+  if (table == nullptr) {
+    LOG_WARN("%s doesn't exist, please check you input", table_name);
+    return RC::SCHEMA_TABLE_NOT_EXIST;
+  }
+
+  // delete index and so on
+  std::string table_file_path = table_meta_file(path_.c_str(), table_name);
+  rc = table->drop(table_file_path.c_str(), table_name);
+
+  if (rc != RC::SUCCESS) {
+    LOG_ERROR("Failed to drop table %s.", table_name);
+    delete table;
+    return rc;
+  }
+
+  opened_tables_.erase(table_name);
+  LOG_INFO("Drop table success. table name=%s", table_name);
+  return RC::SUCCESS;
+}
+
 Table *Db::find_table(const char *table_name) const
 {
   std::unordered_map<std::string, Table *>::const_iterator iter = opened_tables_.find(table_name);

src/observer/storage/db/db.h

@@ -47,6 +47,8 @@ class Db
 
   RC create_table(const char *table_name, int attribute_count, const AttrInfoSqlNode *attributes);
 
+  RC drop_table(const char *table_name);
+
   Table *find_table(const char *table_name) const;
   Table *find_table(int32_t table_id) const;
 

src/observer/storage/default/default_handler.cpp

@@ -170,7 +170,11 @@ RC DefaultHandler::create_table(
 
 RC DefaultHandler::drop_table(const char *dbname, const char *relation_name)
 {
-  return RC::UNIMPLENMENT;
+  Db *db = find_db(dbname);
+  if(db==nullptr){
+    return RC::SCHEMA_DB_NOT_EXIST;
+  }
+  return db->drop_table(relation_name);
 }
 
 Db *DefaultHandler::find_db(const char *dbname) const

src/observer/storage/table/table.cpp

@@ -126,6 +126,47 @@ RC Table::create(int32_t table_id,
   return rc;
 }
 
+RC Table::drop(const char *path, const char *name)
+{
+  RC rc = sync();
+  if(rc!=RC::SUCCESS){
+    return rc;
+  }
+
+  // check
+  if (common::is_blank(name)) {
+    LOG_WARN("Name cannot be empty");
+    return RC::INVALID_ARGUMENT;
+  }
+  LOG_INFO("Begin to drop table %s", name);
+
+  std::string meta_file = table_meta_file(base_dir_.c_str(),name);
+  if(unlink(meta_file.c_str())!=0){
+    LOG_ERROR("Failed to remove meta file");
+    return RC::INTERNAL;
+  }
+
+  std::string data_file = table_data_file(base_dir_.c_str(), name);
+  if(unlink(data_file.c_str())!=0){
+    LOG_ERROR("Failed to remove data file");
+    return RC::INTERNAL;
+  }
+
+
+  // delete indexes
+  const int index_num = table_meta_.index_num();
+  for (int i = 0;i <index_num;i++) {
+    ((BplusTreeIndex*)indexes_[i])->close();
+    const IndexMeta* index_meta = table_meta_.index(i);
+    std::string index_file = table_index_file(base_dir_.c_str(),name,index_meta->name());
+    if(unlink(index_file.c_str())!=0){
+      LOG_ERROR("Failed to remove index,file = %s,errorno = %d",index_file.c_str(),errno);
+    }
+  }
+
+  return rc;
+}
+
 RC Table::open(const char *meta_file, const char *base_dir)
 {
   // 加载元数据文件

src/observer/storage/table/table.h

@@ -54,6 +54,8 @@ class Table
             int attribute_count, 
             const AttrInfoSqlNode attributes[]);
 
+  RC drop(const char *path, const char *name);
+
   /**
    * 打开一个表
    * @param meta_file 保存表元数据的文件完整路径