I'm trying to Export a very large amount of data as XML using plsql (around 80000000 characters). Unfortunately I'm currently unable to use FILE_UTL due to system privileges, and have been suggested to store it in a local table. Annoyingly, this table is cutting off the data at around 800 characters. While I'm aware plsql has a limit of 4000 characters, I'm still unsure how to proceed, and to keep my data stored so I can manually export it, or automatically do so.
TIA
Related
We are using Teradata Fastexport connection in Informatica to export data from few tables by joining them in Source Qualifier query and write to a CSV file. We have around 180 columns to pull, recently we added 2 new columns to this flow and we found that data for few of the records looks junk. We figured out those records and tried to run the SQ query only for those records, to our surprise the columns which were junk earlier now throwing us expected data.
Is there any fast export limitation to export the columns ? or any properties should be increased at Informatica level.
We are clueless on this issue, please help.
obviously editing any column value will change the checksum.
but saving the original value back will not return the file to the original checksum.
I ran VACUUM before and after so it isn't due to buffer size.
I don't have any indexes referencing the column and rows are not added or removed so pk index shouldn't need to change either.
I tried turning off the rollback journal, but that is a separate file so I'm not surprised it had no effect.
I'm not aware of an internal log or modified dates to explain why the same content does not produce the same file bytes.
Looking for insight on what is happening inside the file to explain this and if there is a way to make it behave(I don't see a relevant PRAGMA).
granted https://sqlite.org/dbhash.html exists to work around this problem but I don't see any of these conditions being triggered "... and so forth" is a pretty vague cause
Database files contain (the equivalent of) a timestamp of the last modification so that other processes can detect that the data has changed.
There are many other things that can change in a database file (e.g., the order of pages, the B-tree structure, random data in unused parts) without a difference in the data as seen at the SQL level.
If you want to compare databases at the SQL level, you have to compare a canonical SQL representation of that data, such as the .dump output, or use a specialized tool such as dbhash.
Is it possible to execute an Array DML INSERT or UPDATE statement passing a BLOB field data in the parameter array ? And the more important part of my question, if it is possible, will Array DML command containing BLOB data still be more efficient than executing commands one by one ?
I have noticed that TADParam has a AsBlobs indexed property so I assume it might be possible, but I haven't tried this yet because there's no mention of performance nor example showing this and because the indexed property is of type RawByteString which is not much suitable for my needs.
I'm using FireDAC and working with SQLite database (Params.BindMode = pbByNumber, so I'm using native SQLite INSERT with multiple VALUES). My aim is to store about 100k records containing pretty small BLOB data (about 1kB per record) as fast as possible (in cost of the FireDAC's abstraction).
The main point in your case is that you are using a SQLIte3 database.
With SQLite3, Array DML is "emulated" by FireDAC. Since it is a local instance, not a client-server instance, there is no need to prepare a bunch of rows, then send them at once to avoid network latency (as with Oracle or MS SQL).
Using Array DML may speed up your insertion process a little bit with SQLite3, but I doubt it will very high. Good plain INSERT with binding per number will work just fine.
The main tips about performance in your case will be:
Nest your process within a single transaction (or even better, use one transaction per 1000 rows of data);
Prepare an INSERT statement, then re-execute it with a bound parameter each time;
By default, FireDAC initialize SQLite3 with the fastest options (e.g. disabling LOCK), so let it be.
SQlite3 is very good about BLOB process.
From my tests, FireDAC insertion timing is pretty good, very close to direct SQlite3 access. Only reading is slower than a direct SQLite3 link, due to the overhead of the Delphi TDataSet class.
I am using Asp.net web application for importing the data from Excel cells into SQL server 2008. but while importing some data is perfectly imported but some cells data is cutting. due to that some data is lost. please give solution for this issue.
I think it is not imported the data which is having large size i.e greater than 255 characters. Please let me know the solution for importing the large size cell data.
It sounds like you table schema may be causing this. Make sure that the fields you are importing the data to have an appropriate size. e.g. you may be trying to commit a string of 300 characters to a varchar(255) column.
I'm trying to read a .sql file into SQLite, but I'm getting syntax errors because the file was dumped from MySQL, which can add multiple entries at once, but I'm using SQLite v3.7.7, which can't read more than one entry to a table at a time with the VALUES command.
My understanding is that I either need to upgrade SQLite, or somehow modify the file to read in one entry at a time into the tables. Please note I'm dealing with tens of thousands of entries, so inserting the UNION SELECT command probably won't be very easy.
You need at least SQLite 3.7.11 to use the VALUES syntax you're interested in. But mysqldump has about 100 command-line options. And one of them, --skip-extended-insert, can disable extended inserts. (So you get one INSERT statement per row.) Read the mysqldump documentation, and run the dump again with options that better fit your target.
Or better yet, look at the list of SQLite converter tools.