我正在寻找最好的方法(代码最简单,最快速的方法)来构建存储过程(Oracle 11g),将所有记录(所有字段)从fact_table(源)插入到target_table(目标),但它应该创建一个额外的字段" dynamic_key"它将包含某些列的值,由管道" |"连接。
对于每条记录,"用于构建dynamic_key" 的列的信息存储在rule_table中。
示例(假设所有列都是VARCHAR2):
fact_table(tech_name,dim1, dim2 ,dim3, dim4 ,dim5,otherfields ..) 防爆。 fact_table(' foo',' time',' width',' height',' volume', ' perimeter',otherfields ..)
rules_table(tech_name,filed1,field2,field3)Ex。 rules_table(' foo', dim2 , dim4 )列tech_name用于加入 fact_table和rules_table之间的(f.tecnical_name = r.tecnical_name) 获得专栏。
target_tables(dynamic_key,tecnical_name,dim1,dim2,dim3,dim4, dim5,otherfields ..)
在此示例代码中,存储过程应该:
INSERT INTO target_table(dynamic_key, tecnical_name, dim1, dim2, dim3, dim4, dim5, otherfields..)
VALUES('width|volume', 'foo', 'time', 'width' , 'height', 'volume', 'perimeter', otherfields.. )
我认为最好的方法是使用CURSOR和动态SQL,但是建立dynamic_key非常有效:我必须及时处理和插入一条记录。
答案 0 :(得分:1)
您可以通过以下方式实现这一目标:
SELECT ... USER_TAB_COLS
枚举所有表格列,以创建INSERT
CASE
列构建大型dynamic key
表达式EXECUTE IMMEDIATE
运行生成的语句完整示例:
create table fact_table (tech_name varchar2(30), dim1 varchar2(30),
dim2 varchar2(30), dim3 varchar2(30), dim4 varchar2(30),
dim5 varchar2(30));
insert into fact_table values('foo', 'time', 'width' , 'height', 'volume', 'perimeter');
insert into fact_table values('bar', 'time', 'width' , 'height', 'volume', 'perimeter');
commit;
create table target_table as
select t1.*, cast(null as varchar2(100)) as dynamic_key
from fact_table t1
where 1=0;
create table rules_table(tech_name varchar2(30), field1 varchar2(30), field2 varchar2(30),
field3 varchar2(30));
insert into rules_table values('foo', 'dim2', 'dim4', null);
insert into rules_table values('bar', 'dim1', null, null);
commit;
declare
CRLF constant varchar2(10) := chr(13) ||chr(10);
procedure insert_it is
l_SQL varchar2(4000);
l_columns varchar2(4000);
begin
-- get comma-separated list of columns present in FACT_TABLE
select listagg(column_name, ',') within group(order by column_name)
into l_columns
from user_tab_cols
where table_name = 'FACT_TABLE';
-- build INSERT statement
l_SQL := ' insert into target_table(' || l_columns || ', dynamic_key)' || CRLF ||
' select ' || l_columns || ',' || CRLF ||
' (case tech_name' || CRLF;
-- build case branches from rules table
for cur in (select * from rules_table order by tech_name)
loop
l_SQL := l_SQL || ' when ''' || cur.tech_name || ''' then ' ||
cur.field1 || (case when cur.field2 is not null then '|| ''|'' ||' || cur.field2
else null end)
|| (case when cur.field3 is not null then '|| ''|'' ||' || cur.field3
else null end) || CRLF;
end loop;
-- close case statement and add FROM clause
l_SQL := l_SQL || 'end) from fact_table';
dbms_output.put_line(l_SQL);
execute immediate l_SQL;
end;
begin
insert_it;
end;