I have two tables called Product and Transactions.
In Product 19 records are there and in Transaction 21 records are there.
I am trying to get the matched records from both the tables using of Tmap (inner join).
I am able to load the matched records from the both tables, but I want to fetch the (unmatched records) into the rejected table.
I want to do this parallel in one job.
Find the answer in the screen shots
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I'm Beginner of Debezium concept,
Just Before i created Maven project for debezium integration. i created 2 java classes one is Configuration part and another one is OPERATIONS Part like CREATE,DELETE,UPDATE.
Step 1--: My Configuration part i added few my database related properties like host name port, dbname etc like as uploaded image(1.1).
enter image description here
So i'm inserting one record that (id is 1000) to my table debezium read that record. I take that records inserting some like .. ABC table.
Now i'm Down application(debezium Shut Down) then i'm inserting one Records previously not inserted but after adding snapshot.mode="never" its work fine data inserted (id is 1001).
Here is my issue---> : data inserted along with previous records like when (debezium Shut Down) then restart 1001 and 1000 id also inserted into ABC Table next time Again Down my application (debezium Shut Down) now i'm not inserting any record then Restart my application then again 1001 and 1000 id(s) insert every time with out any operation 2 records inserted.
I Don't want previous related records just i need how many records inserted in (debezium down time that much records i need)
Could you please tell what type of properties i need to add for Resolving this issue.
I have a multi-tenant database in postgres. So, I have one schema per customer and each schema has a fixed set of tables.
When I connect to the DB using Google Data Studio(GDS), I only see the table names without their associated schema.
How do I connect to tables belonging to one or more schemas?
Also, what do I do if my tables have more than 700k rows, as GDS has a limit on number of rows that can be queried right?
You'll have to use the "Custom Query" option instead of the basic table selection if you need anything more complex.
Regarding the row limit. I wasn't aware of the limit, but if that is true I'd suggest using the Custom Query to pre-group your rows in the query into whatever makes sense...days...months...etc to bring the row count down.
Data Studio will likely choke on anywhere near that many rows and make for a horrible user experience. Let Postgres do as much of the heavy lifting as you can.
Answering only: "what do I do if my tables have more than 700k rows, as GDS has a limit on number of rows that can be queried right?"
Not exactly. The limit is on the number of rows returned, not the amount of rows queried. And that matters since Data Studio will almost always push down queries to connectors.
Here's an example: Lets say you have a purchase table in a PostgreSQL db with 1M+ rows where each record is a purchase event. You add this table as a data source in your report and add a bar chart that shows average purchase by customer type. Let's say you have 12 customer types. Data Studio will then push down the GROUP BY clause to the PostgreSQL db. Thus, your result will have only 12 rows of data instead of 1M+. In most chart types, Data Studio will aggregate or page the results thus issuing a query statement that limits the number of rows returned.
You will only run into the limit if you end up creating a scenario where Data Studio cannot issue an aggregation or paging over the query results or if the aggregated results cross the row limit.
I am not able to fetch data when multi table which are having relationship . so can any one help as per the below image
finally i need data like
ORDER_ID, USER_FULL_NAME, PRODUCT_NAME, PRODUCT_PRICE from 3 different table .
please help me out.
Sembast, does not provide a way to query multiple stores in one join query. However getting an entity by id (here a user or a product) is almost immediate (store.record(id).get(db) or store.records(ids).get(db)) so I think your best bet is to query the order_items store and fetch the users and products by ids.
Basically using 3 requests in a transaction to ensure data integrity should perform the join you want.
I have a relational database in access, but I have issues joining tables (first time doing a relational database). I did three queries: on first I got costumers and orders information, on second one I got products and quantities. On third one, I got issues information based in first and second queries with some issues table fields.
Then I did a form with query costumer data and a subform with products information (quantities) and I need a issue form. I added a yes/no field from issues table, and when I tick it in subform, I want to be displayed a issues form to type data issues for each record.
The best I could do was joining "identifier" from "incidencias" table to "identifier" to "pedidos" table. I got what I wanted, but I got the issues form fields locked and greyedo out when I tried to entry data, maybe because I did forms based just in queries (I read that searching in google). when I did the form based only in tables, I got serveral errors and the same field information for all records.
I'm confused about this annotation for an entity field that is of type of another entity:
#BatchFetch(value = BatchFetchType.JOIN)
In the docs of EclipseLink for BatchFetch they explain it as following:
For example, consider an object with an EMPLOYEE and PHONE table in
which PHONE has a foreign key to EMPLOYEE. By default, reading a list
of employees' addresses by default requires n queries, for each
employee's address. With batch fetching, you use one query for all the
addresses.
but I'm confused about the meaning of specifying BatchFetchType.JOIN. I mean, doesn't BatchFetch do a join in the moment it retrieves the list of records associated with employee? The records of address/phone type are retrieved using the foreign key, so it is a join itself, right?
The BatchFetch type is an optional parameter, and for join it is said:
JOIN – The original query's selection criteria is joined with the
batch query
what does this means? Isn't the batch query a join itself?
Joining the relationship and returning the referenced data with the main data is a fetch join. So a query that brings in 1 Employee that has 5 phones, results in 5 rows being returned, with the data in Employee being duplicated for reach row. When that is less ideal, say a query over 1000 employees, you resort to a separate batch query for these phone numbers. Such a query would run once to return 1000 employee rows, and then run a second query to return all employee phones needed to build the read in employees.
The three batch query types listed here then determine how this second batch query gets built. These will perform differently based on the data and database tuning.
JOIN - Works much the same away a fetch join would, except it only returns the Phone data.
EXISTS - This causes the DB to execute the initial query on Employees, but uses the data in an Exists subquery to then fetch the Phones.
IN - EclipseLink agregates all the Employee IDs or values used to reference Phones, and uses them to filter Phones directly.
Best way to find out is always to try it out with SQL logging turned on to see what it generates for your mapping and query. Since these are performance options, you should test them out and record the metrics to determine which works best for your application as its dataset grows.