查询表列数的SQL语句-数据库

SELECT COUNT(*) FROM USER_TAB_COLUMNS WHERE TABLE_NAME=UPPER('legalentity')

MYSQL中的外键：

/*===============================*/
/* DBMS name:      MySQL 4.0           */
/* Created on:     2005-8-9 16:38:37   */
/*===============================*/

drop table if exists Article;

drop table if exists Board;

drop table if exists User;

/*======================================*/
/* Table: Article          　           */
/*======================================*/
create table Article
(
   id                             int                            not null  primary key,
   parent_id                      int,
   index(parent_id),
   foreign key (parent_id) references Article (id) ,
   board_id                       int                            not null,
   index(board_id),
   foreign key (board_id) references Board (id) ,
   article_type                   int                            not null,
   title                          varchar(255)                   not null,
   body                           text,
   create_by                      int                            not null,
   index(create_by),
   foreign key (create_by) references User (id)  ,  
   create_time                    datetime                       not null,
   hits                           int                            not null,
   bytes                          int,
   last_update_by                 int                            not null,
   index(last_update_by),
   foreign key (last_update_by)  references User (id),
   last_update_time               datetime                       not null,
)
type = InnoDB;

/*===================================*/
/* Table: Board                      */
/*===================================*/
create table Board
(
   id                             int                            not null    primary key,
   create_by                      int                            not null,
   index(create_by),
   foreign key (create_by)  references User (id),
   parent_id                      int,
   index(parent_id),
   foreign key (parent_id)  references  Board (id),
   name                           varchar(50)                    not null,
   remark                         varchar(255),
   create_time                    datetime                       not null,
)
type = InnoDB;

/*====================================*/
/* Table: User                        */
/*====================================*/
create table User
(
   id                             int                            not null   primary key,
   name                           varchar(50)                    not null,
   pwd                            varchar(50)                    not null,
)
type = InnoDB;