I have a table A and a table B.
Table B has a relationship with A with the key a_id.
I already created the document in a in table A.
I'm wondering how to insert data in a single query using a doc in table B with foreign key A.
r.db('DB').table('B').insert([{
'b_data': ...,
'a_id': r.db('DB').table('a').filter(r.row['name'] == 'some_name')
} for p in a]).run(conn)
You are on the right track, but ReQL differs from the logic of SQL in that it is usually more like a flow. So your query needs to start with the source of the data so it can flow into the insert portion. So here is a version of what I think you want (in Python format):
r.db('DB').table('a').filter({'name':'some_name}).for_each(
r.db('DB').table('b').insert(
{'name':r.row['name'],'b_data':'something'}
)
).run(conn)
Related
I am new to Hive and have some problems. I try to find a answer here and other sites but with no luck... I also tried many different querys that come to my mind, also without success.
I have my source table and i want to create new table like this.
Were:
id would be number of distinct counties as auto increment numbers and primary key
counties as distinct names of counties (from source table)
You could follow this approach.
A CTAS(Create Table As Select)
with your example this CTAS could work
CREATE TABLE t_county
ROW FORMAT DELIMITED FIELDS TERMINATED BY ','
STORED AS TEXTFILE AS
WITH t AS(
SELECT DISTINCT county, ROW_NUMBER() OVER() AS id
FROM counties)
SELECT id, county
FROM t;
You cannot have primary key or foreign keys on Hive as you have primary key on RBDMSs like Oracle or MySql because Hive is schema on read instead of schema on write like Oracle so you cannot implement constraints of any kind on Hive.
I can not give you the exact answer because of it suppose to you must try to do it by yourself and then if you have a problem or a doubt come here and tell us. But, what i can tell you is that you can use the insertstatement to create a new table using data from another table, I.E:
create table CARS (name string);
insert table CARS select x, y from TABLE_2;
You can also use the overwrite statement if you desire to delete all the existing data that you have inside that table (CARS).
So, the operation will be
CREATE TABLE ==> INSERT OPERATION (OVERWRITE?) + QUERY OPERATION
Hive is not an RDBMS database, so there is no concept of primary key or foreign key.
But you can add auto increment column in Hive. Please try as:
Create table new_table as
select reflect("java.util.UUID", "randomUUID") id, countries from my_source_table;
I know that ROWID is distinct for each row in different tables.But,I am seeing somewhere that two tables are being merged using rowid.So,I also tried to see it,but I am getting the blank output.
I have person table which looks as:
scrowid is the column which contains rowid as:
alter table ot.person
add scrowid VARCHAR2(200) PRIMARY KEY;
I populated this person table as:
insert into ot.person(id,name,age,scrowid)
select id,name, age,a.rowid from ot.per a;
After this I also created another table ot.temp_person by same steps.Both table has same table structure and datatypes.So, i wanted to see them using inner join and I tried them as:
select * from ot.person p inner join ot.temp_person tp ON p.scrowid=tp.scrowid
I got my output as empty table:
Is there is any possible way I can merge two tables using rowid? Or I have forgotten some steps?If there is any way to join these two tables using rowid then suggest me.
Define scrowid as datatype ROWID or UROWID then it may work.
However, in general the ROWID may change at any time unless you lock the record, so it would be a poor key to join your tables.
I think perhaps you misunderstood the merging of two tables via rowid, unless what you actually saw was a Union, Cross Join, or Full Outer Join. Any attempt to match rowid, requardless of you define it, doomed to fail. This results from it being an internal definition. Rowid in not just a data type it is an internal structure (That is an older version of description but Oracle doesn't link documentation versions.) Those fields are basically:
- The data object number of the object
- The data block in the datafile in which the row resides
- The position of the row in the data block (first row is 0)
- The datafile in which the row resides (first file is 1). The file
number is relative to the tablespace.
So while it's possible for different tables to have the same rowid, it would be exteremly unlikely. Thus making an inner join on them always return null.
I need to find a solution to the following problem: there should be a common and single "interface" that I can use in an insert into statement, something like this: insert into INTERFACE (fields) select ...
But there are many tables with the same structure behind the interface which should decide based on list of values (coming in a field) where to put the data. The tables are partitioned by range interval (daily) right now.
I was thinking about having a composite partitioned table which cannot be SELECT-ed to avoid mixing different type of data in a single select query, but creating views on the top of it. In this case the table should be partitioned like this: partition by list FIELD subpartition by range interval. But oracle 12 does not support this.
Any idea how to solve this? (There is a reason why I need a single interface and why I have to store data separately.)
Thank you in advance!
The INSERT ALL syntax can help easily route data to specific tables based on conditions:
create table interface1(a number, b number);
create table interface2(a number, b number);
insert all
when a <= 1 then
into interface1
else
into interface2
select '1' a, 2 b from dual;
i have a slow query whose structure is
select
fields
from
table
join
manytables
join (select fields from tables) as V1 on V1 on V1.field = ....
join (select fields1 from othertables) as V2
join (select fields2 from moretables) as V3
The select subqueries in the last 3 joins are relatively simple but joins agains the, take time. If they were phisical tables it would be much better.
So i found out that i could turn the subqueries to indexed views or to temp tables.
By temp table i do not mean a table who is written hourly like explained here,
but a temp table who is created before the query execution
Now my doubt comes from the fact that indexed views are ok in datawarehouses since they impact the performance. This db is not a datawarehouse but a production db of a non data intense application.
But in my case the above query is executed not often, even if the underlaying tables (the tables whose data would become part of the indexed view) are used more often.
In this case is it ok to use indexed views? Or shuold i favor temp table?
Also table variable with primary key keyword is an alternative.
Is it possible to use two NamedParameterStatement for a single query?
I need to find the ids (Primary and foreign key) for the given value using one NamedParameterStatement, and then all other details related to the ids from other tables.
for example
select code1, code2 code 3
from master table where id in (select id from master table where (date between or any other values))
The description for other codes are in other table
Here I need to pass the result of inner query to the outer query ( I may get the many ids). And I know how to pass the result to another query in JDBC?