Re: More on LINQ Providers
Also the linq-to-llblgen provider was - at least in it's first incarnation - not actually very good. You would constantly come up against unsupported operators, which again just goes to show what a significant effort writing a linq provider is. (As an aside, there is also the LinqToAzure http://linq2azure.com/ API that Joe Albahari helped the Cash Converters team to write, but I have no idea how complete an implementation it is having never used it) From: Greg Keogh Sent: Thursday, October 23, 2014 6:26 AM To: ozDotNet Just a heads-up ... I spent hours working through This Walkthrough to see what it necessary to create a simple LINQ provider. This very primitive example that wraps a web service results in about 10 non-trivial classes with about 500 lines of statements. Most of the code is dense with generics, casts and classes that the average developer probably wouldn't know exist. The sample contains far less than I had hoped to implement even for my most modest needs. I still can't properly understand about 10% of the sample code. Clearly, this area of coding is quite specialised, giving you a glimpse of how compilers work. Given the power of LINQ I can understand why it's so difficult to form and process general expressions, but sadly there are so many arcane classes and techniques involved that I think I will abandon my attempts to create a LINQ provider for now due to lack of spare time to learn something that is too specialised to be of use in general app development. Congratulations to these guys however: Why I hate implementing Linq Developing Linq to LLBLGen Pro (who claims to be the only known civilian who wrote a complete provider) Greg K
Re: LINQ providers
I assume that the ISAM data file system is a pre-requisite? We use an ISAM file system as well and the platform supplier has provided a LINQ provider for us - no such luck with your ISAM provider? It's actually this library from Microsoft: http://managedesent.codeplex.com/wikipage?title=ManagedEsentDocumentationreferringTitle=Documentation I just noticed they've added basic LINQ support to the accompanying PersistentDictionary http://managedesent.codeplex.com/wikipage?title=PersistentDictionaryDocumentationreferringTitle=Home class (which I don't use), so I downloaded the source for a look about how it was done ... I can tell you immediately that unless you have some experience with this sort of coding that it will look like gibberish. *Greg*
Re: LINQ providers
Hi Greg, Are you locked into this specific ISAM provider - can you replace with another? *Regards,* *Steven Parish* *Managing Director* *BusinessCraft Pty Ltd* *Address:* Level 1, 270 Turton Road, New Lambton NSW 2305 *Mail:* PO Box 57, Lambton NSW 2299 *M:* 0417 688 599 | *T:* 02 4965 | *F:* 02 4965 5333 *www.businesscraft.com.au http://www.businesscraft.com/* On 22 October 2014 17:34, Greg Keogh g...@mira.net wrote: I assume that the ISAM data file system is a pre-requisite? We use an ISAM file system as well and the platform supplier has provided a LINQ provider for us - no such luck with your ISAM provider? It's actually this library from Microsoft: http://managedesent.codeplex.com/wikipage?title=ManagedEsentDocumentationreferringTitle=Documentation I just noticed they've added basic LINQ support to the accompanying PersistentDictionary http://managedesent.codeplex.com/wikipage?title=PersistentDictionaryDocumentationreferringTitle=Home class (which I don't use), so I downloaded the source for a look about how it was done ... I can tell you immediately that unless you have some experience with this sort of coding that it will look like gibberish. *Greg*
Re: LINQ providers
Are you locked into this specific ISAM provider - can you replace with another? Do you know of any other in-process, small footprint, transactional, high-performance, high-capacity, zero-configuration, zero-installation ISAM libraries I could replace ESENT with? -- *Greg*
Re: LINQ providers
We have been developing using the synergy/de platform for 30+ years. The synergy isam meets a lot of your criteria. There is a runtime required for their main environment, however they have recently released an entry into the no SQL arena which I believe is free and is just a rebadge of their isam - company name is Synergex from Sacramento in ca / I have a regular monthly Skype call with their CEO this Friday - and can ask some questions for you. They are a great company to deal with. See their web site www.synergex.com the no SQL product is called kittaro Happy to have a chat offline Regards, Steven Parish Sent from my iPhone On 23/10/2014, at 7:26 AM, Greg Keogh g...@mira.net wrote: Are you locked into this specific ISAM provider - can you replace with another? Do you know of any other in-process, small footprint, transactional, high-performance, high-capacity, zero-configuration, zero-installation ISAM libraries I could replace ESENT with? -- Greg
More on LINQ Providers
Just a heads-up ... I spent hours working through This Walkthrough http://msdn.microsoft.com/en-us/library/vstudio/bb546158(v=vs.110).aspx to see what it necessary to create a simple LINQ provider. This very primitive example that wraps a web service results in about 10 non-trivial classes with about 500 lines of statements. Most of the code is dense with generics, casts and classes that the average developer probably wouldn't know exist. The sample contains far less than I had hoped to implement even for my most modest needs. I still can't properly understand about 10% of the sample code. Clearly, this area of coding is quite specialised, giving you a glimpse of how compilers work. Given the power of LINQ I can understand why it's so difficult to form and process general expressions, but sadly there are so many arcane classes and techniques involved that I think I will abandon my attempts to create a LINQ provider for now due to lack of spare time to learn something that is too specialised to be of use in general app development. Congratulations to these guys however: Why I hate implementing Linq http://ayende.com/blog/4675/why-i-hate-implementing-linq Developing Linq to LLBLGen Pro http://weblogs.asp.net/fbouma/developing-linq-to-llblgen-pro-day-1 (who claims to be the only known civilian who wrote a complete provider) *Greg K*
LINQ providers
Folks, I have a simple ISAM data source which can get-by-key or seek on arbitrary indexes. I'm only using an Int32 primary key at the moment and haven't needed to create more indexes so far. For a few thousand records the performance is good, but as it grows and you ask for something like this: var smiths = mydb.ListCustomer().Where(c = c.Surname = Smith).OrderBy(c = c.Postcode); It slows because this query inefficiently Lists the complete database over the primary Int32 index and then uses LINQ-to-objects to give me the result. In this case it's no better than reading a txt file. I realised of course that the real solution is to make my data source a LINQ Provider that it can use its internal DB smarts to answer queries efficiently. By looking at these articles: *Walkthrough: Creating an IQueryable LINQ Provider http://msdn.microsoft.com/en-us/library/vstudio/bb546158(v=vs.110).aspx* and *Enabling a Data Source for LINQ Querying http://msdn.microsoft.com/en-us/library/bb882640.aspx* I realised I was up for a full-time specialist job for a few months. The latter page describes how you can decide to make a *simple*, *medium* or *complex* provider and it warns: Developing a complex provider requires a significant amount of effort. After reading about expression trees I realise this is a highly specialised and complex topic. Even Oren who created RavenDB says it took him longer to write the LINQ provider for the database than it took to write the database itself, which is pretty sobering! I'd still like to turn my data source into a *simple* LINQ provider if possible, but lord knows where to start, maybe at the huge walkthrough in my first link. I found re-linq https://relinq.codeplex.com/ which apparently takes some of the pain of working with expression trees, but I haven't even found a tutorial on it yet. Has anyone got experience or comments on this subject? *Greg K*
Re: LINQ providers
Hi Greg, I assume that the ISAM data file system is a pre-requisite? We use an ISAM file system as well and the platform supplier has provided a LINQ provider for us - no such luck with your ISAM provider? *Regards,* *Steven Parish* *Managing Director* *BusinessCraft Pty Ltd* *Address:* Level 1, 270 Turton Road, New Lambton NSW 2305 *Mail:* PO Box 57, Lambton NSW 2299 *M:* 0417 688 599 | *T:* 02 4965 | *F:* 02 4965 5333 *www.businesscraft.com.au http://www.businesscraft.com/* On 22 October 2014 10:14, Greg Keogh g...@mira.net wrote: Folks, I have a simple ISAM data source which can get-by-key or seek on arbitrary indexes. I'm only using an Int32 primary key at the moment and haven't needed to create more indexes so far. For a few thousand records the performance is good, but as it grows and you ask for something like this: var smiths = mydb.ListCustomer().Where(c = c.Surname = Smith).OrderBy(c = c.Postcode); It slows because this query inefficiently Lists the complete database over the primary Int32 index and then uses LINQ-to-objects to give me the result. In this case it's no better than reading a txt file. I realised of course that the real solution is to make my data source a LINQ Provider that it can use its internal DB smarts to answer queries efficiently. By looking at these articles: *Walkthrough: Creating an IQueryable LINQ Provider http://msdn.microsoft.com/en-us/library/vstudio/bb546158(v=vs.110).aspx* and *Enabling a Data Source for LINQ Querying http://msdn.microsoft.com/en-us/library/bb882640.aspx* I realised I was up for a full-time specialist job for a few months. The latter page describes how you can decide to make a *simple*, *medium* or *complex* provider and it warns: Developing a complex provider requires a significant amount of effort. After reading about expression trees I realise this is a highly specialised and complex topic. Even Oren who created RavenDB says it took him longer to write the LINQ provider for the database than it took to write the database itself, which is pretty sobering! I'd still like to turn my data source into a *simple* LINQ provider if possible, but lord knows where to start, maybe at the huge walkthrough in my first link. I found re-linq https://relinq.codeplex.com/ which apparently takes some of the pain of working with expression trees, but I haven't even found a tutorial on it yet. Has anyone got experience or comments on this subject? *Greg K*
