fix(core): Oracle 复制 INSERT 按行生成语句

* fix(core): emit oracle copy inserts per row

* refactor(core): extract single-row insert dialect check into sql_dialect

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Co-authored-by: zero <zero@zeroMacmini.local>
Co-authored-by: t8y2 <1156263951@qq.com>

crates/dbx-core/src/sql_dialect/capabilities.rs

@@ -64,6 +64,12 @@ pub fn uses_fetch_first(database_type: DatabaseType) -> bool {
     matches!(database_type, DatabaseType::Oracle | DatabaseType::Dameng | DatabaseType::Db2)
 }
 
+/// Oracle 系方言不支持 `INSERT ... VALUES (...), (...)` 多行语法，
+/// 复制为 INSERT 与导出 INSERT 都需按行生成单条语句。
+pub fn uses_single_row_insert_statements(database_type: DatabaseType) -> bool {
+    matches!(database_type, DatabaseType::Oracle | DatabaseType::OceanbaseOracle)
+}
+
 pub fn pagination_strategy(database_type: Option<DatabaseType>, context: PaginationContext) -> TablePaginationStrategy {
     match database_type {
         Some(DatabaseType::Jdbc) => TablePaginationStrategy::AgentMaxRows,