derby的流水號欄位，及範例

CREATE TABLE HOTELAVAILABILITY
    (HOTEL_ID INT NOT NULL, BOOKING_DATE DATE NOT NULL,
 ROOMS_TAKEN INT DEFAULT 0, PRIMARY KEY (HOTEL_ID, BOOKING_DATE));
-- the table-level primary key definition allows you to
-- include two columns in the primary key definition
PRIMARY KEY (hotel_id, booking_date))
-- assign an identity column attribute to an INTEGER
-- column, and also define a primary key constraint
-- on the column
CREATE TABLE PEOPLE
 (PERSON_ID INT NOT NULL GENERATED ALWAYS AS IDENTITY
 CONSTRAINT PEOPLE_PK PRIMARY KEY, PERSON VARCHAR(26));
-- assign an identity column attribute to a SMALLINT
-- column with an initial value of 5 and an increment value
-- of 5.
CREATE TABLE GROUPS
 (GROUP_ID SMALLINT NOT NULL GENERATED ALWAYS AS IDENTITY
 (START WITH 5, INCREMENT BY 5), ADDRESS VARCHAR(100), PHONE VARCHAR(15));

用力找時，反而找不到，不用力找時，反而很多。

http://db.apache.org/derby/docs/10.2/devguide/

http://db.apache.org/derby/docs/10.2/ref/

CREATE TABLE MAPS
(
MAP_ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
MAP_NAME VARCHAR(24) NOT NULL,
REGION VARCHAR(26),
AREA DECIMAL(8,4) NOT NULL,
PHOTO_FORMAT VARCHAR(26) NOT NULL,
PICTURE BLOB(102400),
UNIQUE (MAP_ID, MAP_NAME)
)

always 算是關鍵字，總覺得不太習慣。
整個句子拉得很長!
它的參數也別具風格，
自定一個db也算是愈來愈接近了。
高興的語法。
中文式的開table法。

或是中文欄位，當然是unicode的中文。

所以網路上所有用mysql的範例，要相對的修改。


有不少erp是不用自動加1欄位的。