增加一个Ado数据库连接和一个ado数据库查询,打开连接后在查询中一条条执行删除语句,再提交。
类似:
with adoConn do
begin
ConnectionString := cnString;
Open;
Connected := true;
end;
with adoQuery do
begin
close;
sql.Clear;
sql.Add('delete from tablename1');
execsql;
close;
sql.Clear;
sql.Add('delete from tablename2');
execsql;
......
end;
类似:
with adoConn do
begin
ConnectionString := cnString;
Open;
Connected := true;
end;
with adoQuery do
begin
close;
sql.Clear;
sql.Add('delete from tablename1');
execsql;
close;
sql.Clear;
sql.Add('delete from tablename2');
execsql;
......
end;
alter table b
2 add constraint fk_b_a foreign key (id,dep,birthday)
3 references a (id,dep,birthday)
4 on delete cascade
5 /
SQL> create table a
2 (id varchar2(10),
3 dep varchar2(10),
4 birthday date,
5 name varchar2(10),
6 constraint pk_a primary key (id,dep,birthday))
7 /
Table created.SQL> create table b
2 (id varchar2(10),
3 dep varchar2(10),
4 birthday date,
5 sal number(10))
6 /
Table created.SQL> alter table b
2 add constraint fk_b_a foreign key (id,dep,birthday)
3 references a (id,dep,birthday)
4 on delete cascade
5 /
Table altered.
不能更新