Article
· Jul 7, 2017 19m read
Indexing of non-atomic attributes

Quotes (1NF/2NF/3NF)ru:

Every row-and-column intersection contains exactly one value from the applicable domain (and nothing else).
The same value can be atomic or non-atomic depending on the purpose of this value. For example, “4286” can be
  • atomic, if its denotes “a credit card’s PIN code” (if it’s broken down or reshuffled, it is of no use any longer)
  • non-atomic, if it’s just a “sequence of numbers” (the value still makes sense if broken down into several parts or reshuffled)

This article explores the standard methods of increasing the performance of SQL queries involving the following types of fields: string, date, simple list (in the $LB format), "list of <...>" and "array of <...>".

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Hello,

I'm currently exploring alternatives to CSP/services and ODBC/Sql Maps for access to Caché. I'm not seeing a library which would interest me, so am considering creating one myself.

Does 'CacheConnection' in C# use RPC of some sort, or a defined protocol to communicate with Caché, or does it do so over telnet with scripted commands? I would assume the former. If so, is this a publicly documented protocol that can be implemented by library developers?

Any guidance in this area would be appreciated.

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hi

I restored one database on Server B with EXTSELCT^DBREST command from backup file (this backup file is taken from Server A).

When I execute select some rows from one table, it return error like this,

the same select sql can return correct data in server A

But when I select other rows from same table on Server B, it return correct data.

Why? maybe the backup file corrupted?

Thanks

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"SELECT %SYSTEM.SQL_TableExists('table name') "could work as expected under SQL shell,

but for "CALL %SYSTEM.SQL_TableExists('table name')" does not work (not any error reported, it just show nothing).

Is there any reason why CALL could not be applied to a stored procedure?

Thanks.

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Question
· Nov 28, 2016
spatial data

Hello. I am a student from Syktyvakar Forest Institute(Russia).

I need to make Research : "Databases for working with spatial data
Consider MySQL, PostgreSQL and 1 to choose from". I want to explore Cache with subject library of spatial data.

Help.

Does Someone from the developers write the libraries of spatial data?

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Good day, I would like to find out the size of Caché ObjectScript variable in order to guarantee that my program will not leak, equally in terminal and Caché globals. For example how huge number I can store in that variable ? And what happen in Caché when variable will leak ? How is this behavior treated? (how much memory is reserved for common variable?)

Thanks in advance for your answers.

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Hello...

I need to convert a array (JSON) in a List Of String. I think, there is some method that does it directly.

Something like that:

SAMPLES>set list = ##class(%ListOfDataTypes).$fromJSON("[""a"",""b"",""c""]")

%FromObject+21^%Library.RegisteredObject.1 *%Exception.General Compose Compose %FromObject Unable to map frm %Library.Array instance to %Library.ListOfDataTypes

I have reading about this but I don't found some trick to help me.

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Hi everyone!

We have many severs (DEV, QA and LIVE) besides many other slave servers (about 133) that are running Caché instances. Before writing this utility myself, I would like to know if anyone has done it before. We need to change the SuperUser password and do other credential setups like this on all of these servers and we don't want to do it one by one.

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A few customers have seen this happen, so I thought it would be worth mentioning here on the Developer Community. This could affect users running versions between 2014.1.3 and latest who install or upgrade Wireshark. There is a bug in the Visual C++ 2013 redistributable shipped with the current Wireshark 2.2.1.

This is from Microsoft’s bug report https://support.microsoft.com/en-us/kb/3138367 :

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I would like to start a discussion regarding Caché Objects and Caché SQL.

It is my understanding that the creators of Caché Objects see Caché SQL as the reporting arm of Objects and as such SQL is essential to Caché Objects.

I once met a Caché Objects programmer who was writing code to $Order through the Globals because that person thought that Caché SQL was too slow and inefficient. I attempted to convince the person otherwise.

So, what say you? Is SQL essential to Caché Objects?

Or

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This is a translation of the following article. Thanks [@Evgeny Shvarov] for the help in translation.

This post is also available on Habrahabrru.

The post was inspired by this Habrahabr article: Interval-associative arrayru→en.

Since the original implementation relies on Python slices, the Caché public may find the following article useful: Everything you wanted to know about slicesru→en.

Note: Please note that the exact functional equivalent of Python slices has never been implemented in Caché, since this functionality has never been required.

And, of course, some theory: Interval treeru→en.

All right, let’s cut to the chase and take a look at some examples.

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