I have this sample rows of plate nos with bay nos:
Plate no | Bay no
------------------
AAA111 | 1
AAA222 | 1
AAA333 | 2
BBB111 | 3
BBB222 | 3
CCC111 | 1
Is there a way to make it look like this in a datawindow in powerbuilder?
1 | 2 | 3
------------------------
AAA111 | AAA333 | BBB111
AAA222 BBB222
CCC111
There isn't an simple answer, especially if you need cells to be update-able.
Variable Column Count Strategy
If the number of columns across the top is unknown at development time than you might get by with a "Crosstab" style datawindow but it would be a display only. If you need updates you'll need to do manual data manipulations & updates as each cell would probably represent one row.
Fixed Column Count Strategy
If the number of columns is known (fixed) you could flatten the data at the database and use a standard tabular (or grid) datawindow control but you'll still need to get creative if updates are needed.
If you use Oracle to obtain the data you can use the Pivot and Unpivot function to perform what you are looking for. Here is an example of how to do it:
http://www.oracle.com/technetwork/es/articles/sql/caracteristicas-database11g-2108415-esa.html
Related
I am a beginner at SQL, much more familiar with oob languages, so trying to figure out how to use a loop has been a massive headache. If anyone is familiar with a good resource, I'd really appreciate it?
On to the question.
I have a table where column 1 is percent return, and then column 2 has a starting value and is otherwise empty.
First, I want to update the row 2 column 2 to equal row 1 column 2 amount multiplied by row 2 column 1. Then, for the rest of the table, I want to take the amount in the most recently used cell in column 2 (in our example, it would be row 1), and then multiply it by the percent return in row 3 column 1.
so here's the starting table:
column 1| column 2
,,, | 10
1.1 |
1.2 |
1.05 |
and then here's the resulting table
column 1| column 2
,, | 10
1.1 | 11
1.2 | 13.2
1.05 | 13.86
A “for loop” in SQL is accomplished via a cursor.
But look into the SQL functions LEAD and LAG.
They’ll cover what you’re describing, the ability to know/use values for 2 adjacent rows.
How do I select rows in a table based on a key (PK) from another table. I have selected multiple polygons which is within a geografical region from one layer.
The attributes table from the selected layer look like this:
| Bloknr | Column 1 | Column 2 | Column 3 |
| 111-08 | xqyz | xyzq | qxyz |
| 208-09 | abc | cba | bca |
Where the row in question (row 1) is selected.
I now want to select this row from a nongeographic layer (from a postgresql database) with a table that looks like this:
| BLOKNR | Column 1 | Column 2 | Column 3 |
| 111-08 | cab | bac | cab |
| 208-09 | abc | cba | bca |
| 111-08 | cba | bca | cab |
Where the first and third row is to be selected.
There is about 20.000.000 rows in the postgres table and multiple matches on each bloknr
I work in qgis ver. 3.2 and postgresql with PGadmin4
Any help most appreciated.
UPDATE to answer the comments
It would be simple, if it was a matter of doing it within postgres - it's kind of made for that - but i cannot figure out how to query within qgis i would like not to have to export each table (I have a few, and for each i need multiple selection queries, based on geography) to postgresql - partly because i would like to keep the workflow in qgis, and partly because the export feature in the DB manager of qgis gives me this error - which i think means that i have to make all the tables manually.
" ERROR: function addgeometrycolumn(unknown, unknown, unknown,
integer, unknown, integer) does not exist LINE 1: SELECT
AddGeometryColumn('public','Test',NULL,0,'MULTIPOLYGO...
HINT: No function matches the given name and argument types. You might need to add explicit type casts."
So again any help appreciated.
So i have come up with an answer, that will work in theory.
First make the desired geographical selection and make a new layer with the selection
Then export the layer to the postgis database, with which you are connected
Now it is possible to make queries in postgresql - and PGadmin.
Note that this does not keep the workflow in qgis - and for further processing of statistics etc. one will have to work on the integration between the new postgis layer and selection within this - and it doesn't quite solve the geographical/mapbased selection approach - although it will work
Let's say that for the dimension country I have 4 values and for each of the 4 I have the respective number of Sessions. E.g.
+---------+----------+
| country | Sessions |
+---------+----------+
| Italy | 10 |
| France | 12 |
| Germany | 14 |
| Spain | 16 |
+---------+----------+
I want to compute and output in a scorecard the average number of Sessions, only for those specific countries. So, in the example, the output should be 13.
I tried with the following calculated field but it doesn't work:
Sessions * AVG(CASE
WHEN REGEXP_MATCH(country, '^Italy|France|Germany|Spain.*') THEN 1
ELSE 0 END)
Create a filter based on the country dimension using the Matching RegEx operator.
Then apply this to a scorecard with the metric sessions. In the Data tab on the right hand side, you should be able to click on a little pencil icon for the metric, and choose the aggregation method as average instead of sum.
You may not have this option if you're using the GA connector. In this case, there should be an Average Session metric in the data source.
One way it can be achieved is by using a Filter Control and a Calculated Field:
1) Filter Control
Add the component with the Dimension set to Country and then add a Default Selection (a comma separated list of the required countries):
Italy, France, Germany, Spain
2) Calculated Field (Scorecard)
Sessions / COUNT_DISTINCT(Country)
Google Data Studio Report and a GIF to elaborate:
The Question
One thing that I am confused about is the technical definition of possibly the most basic component of a database: a single value.
Some Examples
I understand and follow (at a minimum) the first three normal forms of database normalization - or so I think. That said, with the introduction of RANGE in PostgreSQL 9.2 I started thinking about what makes a single value.
From the docs:
Range types are useful because they represent many element values in a single range value
So, what are you? Several values, or a single value... nothingness... 42?
Why does this matter?
Because is speaks directly to the Second Normal Form:
Create separate tables for sets of values that apply to multiple records.
Relate these tables with a foreign key.
#1 Ranges
For example, in Postgres 9.1 I had some tables structured like this:
"SomeSchema"."StatusType"
"StatusTypeID" | "StatusType"
--------------------|----------------
1 | Start
2 | Stop
"SomeSchema"."Statuses"
"StatusID" | "Identifier" | "StatusType" | "Value" | "Timestamp"
---------------|----------------|----------------|---------|---------------------
1 | 1 | 1 | 0 | 2000-01-01 00:00:00
2 | 1 | 2 | 5 | 2000-01-02 12:00:00
3 | 2 | 1 | 1 | 2000-01-01 00:00:00
4 | 3 | 1 | 2 | 2000-01-01 00:00:00
5 | 2 | 2 | 7 | 2000-01-01 18:30:00
6 | 1 | 2 | 3 | 2000-01-02 12:00:00
This enabled me to keep an historical record of how things were configured at any given point in time.
This structure takes the position that the data in the "Value" column were all separate values.
Now, in Postgres 9.2 if I do the same thing with a RANGE value it would look like this:
"SomeSchema"."Statuses"
"StatusID" | "Identifier" | "Value" | "Timestamp"
---------------|----------------|-------------|---------------------
1 | 1 | (0, NULL) | 2000-01-01 00:00:00
2 | 1 | (0, 5) | 2000-01-02 12:00:00
3 | 2 | (1, NULL) | 2000-01-01 00:00:00
4 | 3 | (2, NULL) | 2000-01-01 00:00:00
5 | 2 | (1, 7) | 2000-01-01 18:30:00
6 | 1 | (0, 3) | 2000-01-02 12:00:00
Again, this structure would enable me to keep an historical record of how things were configured, but I would be storing the same value several times in separate places. It makes updating (technically inserting a new record) more tricky because I have to make sure the data rolls over from the original record.
#2 Arrays
Arrays have been around for a long time, and while they can be abused, I tend to use them for things like color codes. For example, my project stores information and at times needs to know how to display it. I could create three columns to store red, green, and blue values; but that just seems silly. When would I ever create a foreign key (or even just filter) based on one of the given color codes.
When I created the field it was from the perspective that I needed to store a color in a neutral format so that I could feed anything that accepts a color value. I made the column an array and filled it with the appropriate codes to make the color I want.
#3 PostGIS: Geometry & Geography
When storing a polygon in PostGIS, it stores all the points that make the boundary in a single field. If one point were to change and I wanted to keep an historical record, I would have to store all of the points that have not changed twice in order to store the new polygon along with the old.
So, what is a value? and... if RANGE, ARRAY, and GEOGRAPHY are values do they really break the second normal form?
The fact that some operation can derive new values from X that appear to be components of X's value doesn't mean X itself isn't "single valued". Thus "range" values and "geography" values should be single values as far as the DBMSs type system is concerned. I don't know enough about Postgresql's implementation to know whether "arrays" can be considered as single values in themselves. SQL DBMSs like Postgresql are not truly relational DBMSs and SQL supports various structures that certainly aren't proper relation variables, values or types (pointers, nulls and other exotica).
This is a difficult and sometimes controversial topic however. If you haven't read it then I recommend the book Databases, Types, and the Relational Model - The Third Manifesto by Date and Darwen. It addresses exactly the kind of questions you are asking about.
I don't like your description of 2NF but it's not very relevant here.
In the survey, there is a type of question called Matrix which it's like this:
| Is Friendly | Weather | Comments
===========================================
Sydney | Y | 5 | 'bla'
-------------------------------------------
Singapore | Y | 10 | 'test'
-------------------------------------------
Jakarta | N | 0 | 'test2
-------------------------------------------
Try to get a feedback in term of designing SQL table for question and answer. I could have a design that you can only have 3 label sets (Is Friendly, Weather, Comment) or maybe extended to 10 to be save which means I have 10 columns.
What do you think about this approach, I know this is not relation database in such but at least from query point of view for answer to pull out.
Your thought?
In Sql Server you can make use of PIVOT.
This will allow you to design the table differently.
You would then have a table with columns
EntryType (eg. IsFriendly, Weather, Comment)
City_Region (eg. Sydney, Singapore, Jakarta)
EntryValue (eg. Y, 5, bla)
This will basically give you the functionality to have "dynamic" columns.