I am starting to learn Spring and faced with some issues regarding spring-jdbc.
First, I tried run the example from this: https://spring.io/guides/gs/relational-data-access/ and it worked. Then, I commented lines with droping and creating new tables(http://pastebin.com/zcJHsL1P), in order to not override data, but just get it from db and show it. However, spring showed me error:
Table "CUSTOMERS" not found; SQL statement: ...
So, my question is: What should I do to store my database permanently? I don't want to recreate all time new database, I want create it once and update it.
P.S. I used H2 database. Maybe problem exists in tis db?
That piece of code looks like you are "prototyping" something; so it's easier to automatically create a new database (schema, tables, data) on the fly, execute and/or test whatever you want to...and finish the execution.
If you want to persist your data and only modify/update it, either use H2 with the "file layout" or use MySQL, PostreSQL, etcetera.
By the way, the reason you are getting Table "CUSTOMERS" not found; SQL statement: ... is because you are using H2 as an in-memory database and every time you start your application you need to re-create the tables and populate them with data.
Related
I am new SQL and I was wondering if there is any quick way of getting a global "view" of a new database (if for example you are starting to use a database you know nothing about and you want to just get a global idea of how the entire database looks like).
In other words is there a way to :
Maybe get some graphical representation of the database? - a sort of diagram that shows the relation between all tables
Maybe do some sort of query that could return the no. of rows, no. columns (and ideally column names) of each table in the database?
Apologies if this is a really basic question, I am very new to SQL. I am currently using PostgreSQL and PgAdmin4. Thanks
I have to extract data from Oracle tables and copy them to PostgreSQL. I am able to map both the input and output files. On running the connector component I get the proper row fetching graphical image, but when I go to the table there is no such data.
This one is for PostgreSQl to PostgreSQL:
TRACE_DEBUG result
After trace debug this is what I get
Are you trying to read and write on the same table in Input and Output ? (this could be a problem).
What kind of action are you using in the output , insert, update, insert or update ?
Did you check if there is a lock on your output table ?
Depending on the settings on your database connection, you may need to turn on auto commit or add an explicit commit component at the end of the Flow.
How is the output component configured ?
operation type : insert?
is it doing a lookup?
is the table name correct ?
did you check the error code global value for the component After it finishes ?
I have a Job in talend that inserts data into a table.
Can I get this SQL sentences (ie "insert into tabla(a,b)values(....)")?
You can see the data inserted by adding tLogRow but if you want to see the generated insert on real time you can use the debugger.
For example, for the following job:
Above you can see the data inserted from an excel file to a mysql table. This was generated using tLogRow. But if you want the sql generated sentence, by using the debug you can see it here:
Hope to help.
You could simply place a tLogRow component either before or after your database output component to log things to the console if you are interested in seeing what data is being sent to the database.
I think it's impossible to see (it could be nice as an improvement in new releases). My problem, was when I change de source of my database output (Oracle SID to Oracle RAC), the inserts were made in the older database.
I fix it change the xml code in the "item" file. With the change older params attached to Oracle SID were stil there.
Thanks a lot!! Have a nice weekend Goon10 and ydaetskcoR!
You can check the generated JAVA code. You'll see an:
INSERT INTO (columns) VALUES (?,?,?)
thats the insert preparedStatement. Talend uses preparedStatements to do the inserts, thus only 1 insert will be generated and sent. In the main part of the component it will call
setString(value,position)
Please refer to: http://docs.oracle.com/javase/tutorial/jdbc/basics/prepared.html
I have a stored procedure in my project under sql/my_prod.sql
there I have my function delete_entity
In my entity
#NamedNativeQuery(name = "delete_entity_prod",
query = "{call /sql/delete_entity(:lineId)}",
and I call it
Query query = entityManager.createNamedQuery("delete_entity_prod")
setParameter("lineId",lineId);
I followed this example: http://objectopia.com/2009/06/26/calling-stored-procedures-in-jpa/
but it does not execute the delete and it does not send any error.
I haven't found clear information about this, am I missing something? Maybe I need to load the my_prod.sql first? But how?
JPA 2.1 standardized stored procedure support if you are able to use it, with examples here http://en.wikibooks.org/wiki/Java_Persistence/Advanced_Topics#Stored_Procedures
This is actually they way you create a query.
Query query = entityManager.createNamedQuery("delete_entity_prod")
setParameter("lineId",lineId);
To call it you must execute:
query.executeUpdate();
Of course, the DB must already contain the procedure. So if you have it defined in your SQL file, have a look at Executing SQL Statements from a Text File(this is for MySQL but other database systems use a similar approach to execute scripts)
There is no error shown because query is not executed at any point - just instance of Query is created. Query can be executed by calling executeUpdate:
query.executeUpdate();
Then next problem will arise: Writing some stored procedures to file is not enough - procedures live in database, not in files. So next thing to do is to check that there is correct script to create stored procedure in hands (maybe that is currently content of sql/my_prod.sql) and then use that to create procedure via database client.
All JPA implementations do not support calling stored procedures, but I assume Hibernate is used under the hood, because that is also used in linked tutorial.
It can be the case that current
{call /sql/delete_entity(:lineId)}
is right syntax for calling stored procedure in your database. It looks rather suspicious because of /sql/. If it turns out that this is incorrect syntax, then:
Consult manual for correct syntax
Test via client
Use that as a value of query attribute in NamedNativeQuery annotation.
All that with combination MySQL+Hibernate is explained for example here.
In my application as I release a new version, I alter my existing database tables by adding a new table or altering existing tables in SQlite.
I have written the same in script/text file and want to just import in a form of batch directly into existing database where these queries will execute once.
I know that i can do same by writing each alter query separately but this will also increase execution time and time for writing question.
Any ideas on how I can achieve this?
One thing that I used to was to keep an array of colums for each table, like
persons = {[ fname, lname, address, zip ]}
then I also have another version array, that tells me I have for version 1, persons, 4 colums.
Then when I updated the application, and add f.ex. gsm to the persons, I update the array and the count. Then I run the query on the database sqlite_master, parse the data
you can run '.schema persons' to get the create statement. This is just work you do once, and you never run alter table on tables up to date this way. You need to be organized.