BULK COLLECT句の使用,PolarDB:多数の行で構成される結果セットを返すSQLステートメントは、結果セット全体を転送するためにデータベースサーバーとクライアントの間で常にコンテキストを切り替える必要があるため、可能な限り効率的に動作していない可能性があります。 コ
BULK COLLECT 子句用于指定结果集到集合的这种聚合。 BULK COLLECT 子句可与 SELECT INTO、FETCH INTO 和 EXECUTEIMMEDIATE 命令一起使用,也可与 DELETE、INSERT 和 UPDATE 命令的 RETURNING INTO 子句一起使用。其中每个语句和子句将在以下各节中予以说明。 SELECT BULK COLLECT BULK COLLECT 子句可与 SELECT INTO 语...
--差异是FOR循环的SELECT INTO逐行提取并绑定到记录变量,而BULK COLLECT则一次即可提取所有行并绑定到记录变量。即谓批量绑定。 二、使用LIMIT限制FETCH数据量 在使用BULK COLLECT 子句时,对于集合类型,如嵌套表,联合数组等会自动对其进行初始化以及扩展(如下示例)。因此如果使用BULK COLLECT子句操作集合,则无需对集合进...
PostgreSQL’s PL/pgSQL doesn’t have built-in features that are equivalent to Oracle’s PL/SQL features, such as BULK COLLECT, FETCH, or FORALL. However, you can choose from multiple approaches to achieve similar functionalities. In this section, we compare four such approaches. T...
采用bulk collect可以将查询结果一次性地加载到collections中,而不是通过cursor一条一条地处理。 可以在select into,fetch into,returning into语句使用bulk collect。 注意:在使用bulk collect时,所有的into变量都必须是collections create table t_test as selec
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您应该首先执行健全性检查,或者使用Greatest[Django-doc]: from django.db.models import Valuefrom django.db.models.functions import Greatestself.bookmarks_count = Greatest(F('bookmarks_count') - 1, Value(0))self.save()self.refresh_from_db(fields=('bookmarks_count',))if self.bookmarks_count ==...
PostgreSQL has itsCOPY command, , MySQL itsLOAD DATA INFILEormysqlimport utility, Oracle has itsBULK INSERT,BULK COLLECT and FORALL, and so on. Data files won’t necessarily be stored on the machine hosting the database, and so a script executed on a workstation is much better placed...
EXECUTEIMMEDIATE'sql_expression;'BULKCOLLECTINTOcollection [,...] [USING{[bind_type] bind_argument} [, ...]}]; collection 指定集合的名称。 bind_type 指定 bind_argument 的参数模式。 bind_type 为 IN 时指定 bind_argument 包含传递给 sql_expression 的值。
The NFs collect and export the statistics separately to an aggregator node in the 5G architecture. The receiver correlates the statistics from the NFs using the node-names or any other information that is configured as part of the bulk statistics configuration. Any EMS...