在PostgreSQL 中,CREATE TABLE语句用于创建一个新的表。表是数据库的基本构建块,用于存储数据。通过定义表结构,可以组织和管理数据的存储方式。本文将详细介绍在 PostgreSQL 中如何使用CREATE TABLE语句,包括其基本语法、各种数据类型、约束条件、表的选项以及常见操作示例。 1. 基本语法 在PostgreSQL 中,CREATE TABLE的...
I - 嵌套表(Nested tables) TYPE nested_type IS TABLE OF VARCHAR2 ( 30 ) [not null]; -- 值为 varchar2 的数组,下标为默认 int ; 1. 2. 特征:可删除信息,下标不变 II - 变长数组(Variable-Sized Arrays) TYPE Calendar IS VARRAY ( 366 ) OF NUMBER ; --366 个 number 数组,下标 1-366(...
INSERT INTO table_name[ (column1 [, column2 ]) ] SELECT[ *|column1 [, column2 ]]FROMtable1[, table2 ][ WHERE VALUE OPERATOR ] 实例 假设COMPANY1 的结构与 COMPANY 表相似,且可使用相同的 CREATE TABLE 进行创建,只是表名改为 COMPANY1。现在把整个 COMPANY 表复制到 COMPANY1 首先给出对应两...
publicSystem.Threading.Tasks.TaskCreateTableAsync(stringtableName, System.Threading.CancellationToken cancellationToken =default); Parameters tableName String The name assigned to a table of entries. cancellationToken CancellationToken TheCancellationTokento monitor for cancellation requests. The defau...
seq"INCREMENT 1MINVALUE 1MAXVALUE 99999999START 1CACHE 1;ALTER TABLE "public"."control_alarm_info_uid_seq " OWNER TO "postgres";接下来创建“父表”，-- Table: control_alarm_info-- DROP TABLE control_alarm_info;CREATE TABLE control_alarm_info(uid bigserial NOT NULL,status bigint,create_...
createtabletest_id ( idinteger ); 1. 2. 3. 4. 创建触发器函数: 说明:触发器每隔1000笔数据会插入一个新表中,当然id 需要是连续不重复的情况. dropfunction if exists func_trigger_insert_test_id; createorreplace function func_trigger_insert_test_id() ...
CREATE TABLE tbl AS (SELECT (row_number() over())::integer "id", "col" FROM tbl2) Code is getting stuck (cursor.execute never returns), killing the transaction with pg_terminate_backend removes the query from the server, but the code is not released. Yet in this case, the target ...
ALTER TABLE "public"."control_alarm_info_uid_seq " OWNER TO "postgres"; 接下来创建“父表”, -- Table: control_alarm_info -- DROP TABLE control_alarm_info; CREATE TABLE control_alarm_info ( uid bigserial NOT NULL, status bigint, ...
1.建立一个名为my_table的表,包含id、name和age三个列: CREATE TABLE my_table ( id SERIAL PRIMARY KEY, name VARCHAR(50) NOT NULL, age INT NOT NULL ); 2.根据已有的表(my_table),创建一个新表(new_table),并将id列的数据类型更改为BIGINT: CREATE TABLE new_table AS ( SELECT id::BIGINT,...
在一个存储过程中: with会创建临时表吗?存放在哪里? 如果with也会创建临时表,那么与手工create table 创建临时表,用完再drop table,在效率上有什么区别?