Struct MemoryEngine 

pub struct MemoryEngine { /* private fields */ }

内存存储引擎实现

Implementations

impl MemoryEngine

pub fn new() -> Self

pub fn create_index(&mut self, table: &str, column: &str) -> DbResult<()>

为表列创建索引（单列，向后兼容）

pub fn create_composite_index( &mut self, table: &str, columns: &[&str], ) -> DbResult<()>

为表列创建复合索引

pub fn create_unique_index( &mut self, table: &str, columns: &[&str], ) -> DbResult<()>

创建唯一复合索引

pub fn drop_index(&mut self, table: &str, column: &str) -> DbResult<bool>

删除索引

pub fn drop_composite_index( &mut self, table: &str, columns: &[&str], ) -> DbResult<bool>

删除复合索引

pub fn has_index(&self, table: &str, column: &str) -> bool

检查列是否有索引

pub fn has_composite_index(&self, table: &str, columns: &[&str]) -> bool

检查复合索引是否存在

pub fn get_index(&self, table: &str, column: &str) -> Option<&BTreeIndex>

获取索引（不可变引用，单列）

pub fn get_composite_index( &self, table: &str, columns: &[&str], ) -> Option<&BTreeIndex>

获取复合索引（不可变引用）

pub fn get_index_mut( &mut self, table: &str, column: &str, ) -> Option<&mut BTreeIndex>

获取索引（可变引用，单列）

pub fn get_composite_index_mut( &mut self, table: &str, columns: &[&str], ) -> Option<&mut BTreeIndex>

获取复合索引（可变引用）

pub fn drop_table_indexes(&mut self, table: &str)

删除表的所有索引

pub fn get_row_count(&self, table: &str) -> DbResult<usize>

获取表的行数

pub fn remove_from_index( &mut self, table: &str, column: &str, key: &DbValue, row_id: RowId, )

从索引中删除键值对（用于 delete 操作，单列）

pub fn remove_from_composite_index( &mut self, table: &str, columns: &[&str], key: &[DbValue], row_id: RowId, )

从复合索引中删除键值对

pub fn add_to_index( &mut self, table: &str, column: &str, key: DbValue, row_id: RowId, )

向索引添加键值对（用于 insert 操作，单列）

pub fn add_to_composite_index( &mut self, table: &str, columns: &[&str], key: Vec<DbValue>, row_id: RowId, )

向复合索引添加键值对

pub fn find_best_index( &self, table: &str, filter_columns: &[&str], ) -> Option<(&IndexMeta, &BTreeIndex)>

查找最佳索引

pub fn serialize(&self) -> Result<SerializableEngineData, String>

序列化引擎数据（用于快照）

pub fn deserialize(data: SerializableEngineData) -> Self

从序列化数据恢复（用于快照加载）

Trait Implementations

impl Default for MemoryEngine

fn default() -> Self

Returns the “default value” for a type.

impl StorageEngine for MemoryEngine

fn create_table(&mut self, schema: TableSchema) -> DbResult<()>

创建表

fn drop_table(&mut self, name: &str) -> DbResult<()>

删除表

fn has_table(&self, name: &str) -> bool

检查表是否存在

fn get_schema(&self, name: &str) -> DbResult<TableSchema>

获取表 schema（返回克隆，支持锁守卫场景）

fn insert(&mut self, table: &str, row: Row) -> DbResult<RowId>

插入行

fn get(&self, table: &str, row_id: RowId) -> DbResult<Option<Row>>

获取行（返回克隆，支持锁守卫场景）

fn update(&mut self, table: &str, row_id: RowId, values: Row) -> DbResult<()>

更新行

fn delete(&mut self, table: &str, row_id: RowId) -> DbResult<Option<Row>>

删除行

fn scan(&self, table: &str) -> DbResult<Vec<(RowId, Row)>>

扫描全表（返回克隆，支持锁守卫场景）