Questions in topic: "querying data"

Reading WFS in defined portions

fikusas — Tue, 30 Apr 2019 08:31:18 GMT

I have to read all the WFS features, but it can't be sequential read, because server crashes then using this method (feature count is ~3 000 000). I managed to read in all features with 10 different WFS readers and XML filtering by attribute. Is there any simpler/faster way to pull it? For example it is possible to somehow read first 100k features, then request another 100k and so on?

Reading only required feature types in FeaturReader

fikusas — 星期四,2019年4月11日12:22:17格林尼治时间

< div class = " fr-view clearfix " > < p >我有下ing workflow:

1. SDE reader reads the polygon feature which will be used for clipping feature types;

2. FEATURE_TYPES public parameter is fetched. It lists what feature types to read;

3. A few Testers and FeatureReaders is used (depending how many layers are in the DB):

If FEATURE_TYPES contains FeatureX When FeatureReader is initiated to read only what FeatureX;

4. All features read are passed on to the Clippee, etc.

Is there any better workflow which reduces Testers and FeatureReaders to be used? I tried using one FeatureReader and query the feature types to read, but FeatureReader always reads all the features and passes only the ones, what are queried. This is not good, considering the different DB features have millions objects and reading all of them is time consuming.

So if DB contains, for exmaple 60 layers, I need to use 60 Testers and 60 FeatureReaders. It's insane.

XML filter for WFS: filtering multiple values (more than 2)

fikusas — Thu, 31 Jan 2019 13:07:12 GMT

I'm having a problem using WFS XML filter. I'm trying to read only 6 features from entire dataset and I get the following error:

I wrote query in SQL and need to convert it to XML:

"SAV_ID" IN (21,23,25,55,56,88)

Interestingly when I'm quering only 2 of thoses features, I get no errors. XML filter (working one) for 2 features is:

   SAV_ID 21   SAV_ID 23

I tried the following variants (for more than 2 features):

(1) (gives error)

   SAV_ID 21   SAV_ID 23   SAV_ID 25   SAV_ID 55

(2) (gives error)

   SAV_ID 21   SAV_ID 23     SAV_ID 25   SAV_ID 55

(3)

   SAV_ID 21 23 25 55

Last one (3) downloads all the features. Any help on that?