informix日期函数_informix_informix rownum(3)

ALTER TABLE items

ADD (item_weight DECIMAL(6,2) NOT NULL BEFORE total_price)

//添加字段

ALTER TABLE cust_calls

ADD ref_order INTEGER REFERENCES orders (order_num) BEFORE user_id

//添加外键

ALTER TABLE catalog DROP CONSTRAINT aa 删除外键约束

ALTER TABLE catalog ADD CONSTRAINT //添加新的外键约束

(FOREIGN KEY (stock_num, manu_code) REFERENCES stock

ON DELETE CASCADE CONSTRAINT ab)

ALTER TABLE items

ADD (unit_price MONEY (6,2) CHECK (unit_price > 0) )

CREATE TABLE tab1 (i1 int, i2 int, i3 int);

CREATE TABLE tab2 (i4 int, i5 int);

CREATE TRIGGER col1trig UPDATE OF i2 ON tab1

BEFORE(INSERT INTO tab2 VALUES(1,1));

ALTER TABLE tab2 DROP i4; 删除键

ALTER TABLE items MODIFY (quantity SMALLINT DEFAULT 1 NOT NULL) 修改

ALTER TABLE stock MODIFY (description LVARCHAR(3072))

CREATE DATABASE vehicles（） IN research（空间）

CREATE DATABASE vehicles WITH BUFFERED LOG 缓存日志

CREATE DATABASE employees WITH LOG MODE ANSI 模式

如何查看一个表的段数目。

在informix的sysmasters库中，通过执行

select count(*) from sytends where tabname="表名"

表sytend记录了各个表每个段的大小和地址信息。

dbaccess - -<<!

database sysmaster;

select dbsname,tabname,

count(*) num_of_extents,

sum( pe_size ) total_size

from systabnames,sysptnext

where partnum = pe_partnum

group by 1, 2

order by 3 desc,4 desc;

close database;

!

例子1、和UNITS合用，指定日期或时间单位(year,month,day,hour,minute,seond,fraction)：

let tmp_date = today + 3 UNITS day

例子2、let tmp_date = MDY(10,30,2002)-- 2002-10-30

例子3、let tmp_date = today + interval(7) day to day--当前时间加上7天；

注：该功能与1相似；

例子4、EXTEND转换日期或日期时间值

let tmp_inthour = extend(datetime1,hour to hour)

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