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jollybandit

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About jollybandit

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LabVIEW Information

  • Version
    LabVIEW 2013
  • Since
    2009
  1. drjdpowell Many thanks for your time and constructive advice. There is the intension to also use this toolkit and SQLite dll with an application that has a much lower thoughput. This raises a few additional questions :- 1) practically how many reference connection are allowed (if any more than 1) allowing simulltaneous reading and writing to an SQLite file - are there any introduced deficiencies by instigating this practice? 2) in the senario of having multiple parallel loops, requiring access to the same SQLite database file (i.e simulltaneous reading and writing). is it a better practice to open several SQLite file references and managing these independantly in each of the loops?. Alternatively, is it better practice to use a single reference shared across all loops with a single coordinator for the finalise and close? 3) in the senario of multiple asynchronious writes and reads to an SQLite DB file, is it better to begin and commit and close on each loop execution (for insert / read) or create a single reference and only closing on the close of application, for high durability and integrity? 3a) does this latter method put the database at increased risk of locking? 4) On the generation of a runtime error will the LabVIEW VI SQLite finalize / close functionaliity handle this errror event and cleanly close the SQLite db reference or do i need to put in front of this a 'clear errors vi' Many thanks again for your help and Advice Greg
  2. Thakyou in advance for the offer to examine / improve the code. I have attached a Zip file of 1) test file generator 2) top level SQLite performance evaluation code written 3) XLS containg the timming results obtained. I will be very interested in your comment and coding improvements (with hopefully possible effeciency and file size improvements). I am aware of the SQLite.Org website - consequently, i also found a SQLite error vi that has in its block diagram view a well document summary of the possible errors and there structure / composition. Many thanks & Cheers Greg Testing_SQLite.zip
  3. Good day to all Lava users I am New to the envoroment of SQLite and have been experimenting with the tool kit . I have a few Questions that i hope someone will kindly answer and clarify for me and put me in good sted for the project i am about to commence. i seak answers to 1) at run time does the toolkit Vi's returned errors, if so, what are they? 2) Within the SQLite read loop,is it a good practise to wire the error cluster to the while- loop stop button? 3) i have been comparing a LabVIEW spreadsheet file write \ reads to SQLite file size, times for speeds against similar actions. Firstly, a) What is the format of the SQLite created file data stored as - ASCII? BINARY? b) Is any compression used ? or is it something needing enabling? The reason i ask this If i compare the output files on size they are comparable Spreedsheet 30MB (Write 5423ms Read and filter 21681ms), and SQLite 36MB (Write 7539ms, read/filter 528) - this is for the same write file data set of 200000 rows X 7 elements and read/filter ( block insert using the prepare and commit VI's) . a) should this be the case that the SQLite file will be larger in physical disk size? b) and longer to write? 4) i also discovered that when purging data from the SQLite table the file size apperars to remains constant ? Subsequently i have discovered the Vacuum function how is this bet employed? 5) My intension is to use this in an Action / Events tracker in an Application is ther ay recomendations or tricks to ensure optium data capture - especially for those unexpected power/ system crashes? 6) finally during muy programming i have fould that it is possible to accadently lock a SQLite file when capturing and handling an error during the prcessing of an event in an JKI state machine - how do you unlock the SQLite tables? . Many thanks Greg
  4. Whilst that is fine i was endevouring for a more Labview refined way of doing this such that it wasn't dependant onembedded 'sql' coding in my vi(more Generic for any db). I also notce (as shown in the third labview code snipett) that if i pass in the name of the stored procedure i get all the elements as part of the stored user procedure plus an additional parameter called @return_Value - which is not in my written stored procedure . Is this something Labview inserts / generates or is it some function of the setup of the database itself???
  5. Need assistance in resolving an issue with calling MSSQL 2008 server side user stored_Procedures. I have currently been writing and executing MSSQL code to call the procedure names of the user stored procedures which i then use with the LabVIEW DB Tools Create Parameterized Query VI. Is there a native LabVIEW coding which is able to get the list of the user stored procedures from the MSSQL database? i have attached code segment that i am currnetly using. Once i have the user Stored Procedure names i have already worked out how to call the associated input /output/ parameters with there details Thanking you in advance for your assistance
  6. Hi all I'm Relatively new to the LabVIEW database tool kit and have worked my way through to successfully have connectivity to a SQL 2005 and Mysql database servers in which queries returned both tables and contained data. The core system is a SQL server 2005 with a developed extension table held on a remote database. Read access is only granted to the core system. The aim is to either link these databases through some "Labview linking (composite)" or "SQL Linking" function to return query results across unions on both databases. I am able to establish individual connectivity to each DB successfully and perform queries. But lack knowledge on and experience on joining two remote databases within the one LABVIEW sql query? For the sake of normalisation and due too large inefficiency overheads we don’t want to have a duplication of the data table on the remote system database where our newly created tables reside.. Can this linking be done? Could someone point me to some good LabVIEW Database examples illustrating above? Or give an explanation? With in a database there are Char and Varchars but LabVIEW has only strings. How do you best define and handle these in LABVIEW for columns of this type descriptions in a Database? Cheers Regards Gregory Nicholls
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