I am using Web2Py smart grid to show the content on the Web.
Since in the database there are some duplicated entries and I would like to hide it some the web. Which I believe there is no way to configure the smart grid. I would need to create a shadow table, which the duplicated entries are removed, for that table.
However I would like to use the shadow table as a subset of the original table - all modification will be made on the original table. And the shadow table provide a view for the original table. But unfortunately the shadow table doesn't work in this way.
How could I make the shadow table effectively get a subset of the original table? Thanks in advance.
distinct eliminates duplicates
create view my_view as
select distinct *
from t
select *
from my_view
Related
Is there any way to create a postgis table with existing style from layer_styles table? Say for example i have so many styles stored in layer_styles table. I need to assign one of the style from layer_styles table to the new table which i am going to create. Can that be done using postgresql during table creation using sql command?
You need to identify the layer IDs of interest (or name, or any column you want) and to create the new table using this data+structure. However using the style in this secondary table may not be that easy
create table public.layer_styles_2 as
(select * from public.layer_styles where id in (2,3));
I have a view view_a in my database on which several other views depend (view_b, view_c, etc.)
I need to convert view_a into a table, because I no longer want the information in this relation to be dynamic and I need the capability to edit rows manually.
Can I replace view_a with a table without doing a DROP CASCADE and redefining all views that reference view_a?
Clarification: I want view_b and view_c to continue to reference view_a (now a table). I want to replace a view with a table, not have a table in addition to a view.
I was able to resolve this without tracking down and redefining all objects that depend on view_a, at the expense of adding one level of useless redirection.
-- create a copy of the result of view_a
CREATE TABLE table_a AS SELECT * FROM view_a;
-- redefine view_a to its own result
CREATE OR REPLACE VIEW view_a AS SELECT * FROM table_a;
I am new to postgreSQL. Is there any way to insert row in postgreSQL pgAdmin without using SQL Editor (SQL query)?
The accepted answer is related to PgAdmin 3 which is outdated and not supported.
For PgAdmin 4 and above, the application is running in the browser.
After you create your table, you have to make sure that your table has a primary key otherwise you couldn't edit the data as mentioned in the official documentation.
To modify the content of a table, each row in the table must be
uniquely identifiable. If the table definition does not include an OID
or a primary key, the displayed data is read only. Note that views
cannot be edited; updatable views (using rules) are not supported.
1- Add primary key
Expand your table properties by clicking on it in the pgAdmin4 legend. Right-click on 'Constraints', select 'Create' --> 'Primary Key'to define a primary key column.
2- View the data in excel like format
Browser view, right-click on your table --> select View/Edit Data --> All Rows
3- Add new row / Edit data
On the Data Output tab at the bottom of the table below the last row, there will be an empty row where you can enter new data in an excel-like manner. If you want to make updates you can also double click on any cell and change its value.
4- Save the changes
Click on the 'Save' button on the menu bar near the top of the data window.
I think some answers don't provide an answer to the original question, some of them insert records but with SQL statements and the OP clearly said WITHOUT, so I post the right answer: (Step by Step)
Alternatively you can use the query tool:
INSERT INTO public.table01(
name, age)
VALUES (?, ?);
use the lightning icon to execute.
You can do that without the SQL editor, but it's better to do this by queries.
Although, in pgAdmin, there is an option which you can click to have an excel-like window where you can add and update data in a table without using SQL language. Please select a table which you want to add a row first and click on the next icon here below.
Editing table data without primary key is forbidden
If your tables don't have a primary key or OIDs, you can view the data only.
Inserting new rows and changing existing rows isn't possible for the Edit Data tool without primary key.
Use INSERT:
INSERT INTO tablename (field1, field2) values ('value1', 2);
on pgAdmin 4, right-click on the table and use the item like below. You can also use that script in the background.
Finally, to watch the inserted data do like below. You can also use that script in the background.
All the above are correct answers. I just want to add that : When u create a table, make sure u have atleast one column as PRIMARY_KEY. Then, just follow the GUI : View/Edit data. U can add row as the last row of the table
As an update, the icon for the save button is different in pgAdmin 4.
This is how the menu should look after right-clicking on the table you want to insert into and hovering over "View/Edit Data".
After adding rows, either press F6 (on Ubuntu) or click the icon that looks like a stack of discs (database icon) with a lock on it.
Zoomed in:
Wide View:
Oh helloes!
I have two tables, first one (let's call it NameTable) is preset with a set of values (id, name) and the second one (ListTable) is empty but with same columns.
The question is: How can I insert into ListTable a value that comes from NameTable? So that if I change one name in the NameTable then automagically the values in ListTable are updated aswell.
Is there INSERT for this or does the tables has to be created in some special manner?
Tried browsing the manual but without success :(
The suggestion for using INSERT...SELECT is the best method for moving between tables in the same database.
However, there's another way to deal with the auto-update requirement.
It sounds like these are your criteria:
Table A is defined with columns (x,y)
(x,y) is unique
Table B is also defined with columns (x,y)
Table A is a superset of Table B
Table B is to be loaded with data from Table A and needs to remain in sync with UPDATEs on Table A.
This is a job for a FOREIGN KEY with the option ON UPDATE CASCADE:
ALTER TABLE B ADD FOREIGN KEY (x,y) REFERENCES A (x,y) ON UPDATE CASCADE;
Now, not only will it auto-update Table B when Table A is updated, table B is protected against containing (x,y) pairs that do not exist in Table A. If you want records to auto-delete from Table B when deleted from Table A, add "ON UPDATE DELETE."
Hmmm... I'm a bit confused about exactly what you want to do or why, but here are a couple of pointers towards things you might want to take a look at: table inheritance, triggers and rules.
Table inheritance in postgresql allows a table to share the data of a another table. So, if you add a row to the base table, it won't show up in the inherited table, but if you add a row to the inherited table, it will now show up in both tables and updates in either place will reflect it in both tables.
Triggers allow you to setup code that will be run when insert, update or delete operations happen on a table. This would allow you to add the behavior you describe manually.
Rules allow you to setup a rule that will replace a matching query with an alternative query when a specific condition is met.
If you describe your problem further as in why you want this behavior, it might be easier to suggest the right way to go about things :-)
My current query looks something like this:
SELECT SUBSTR(name,1,1), COUNT(*) FROM files GROUP BY SUBSTR(name,1,1)
But it's taking a pretty long time just to do counts on a table that's already indexed by the name column. I saw from this question that some engines might not use indexes correctly for the SUBSTR function, and in fact, sqlite will not use indexes for SUBSTR(string,1,1).
Is there any other approach that would utilize the index and net me some faster queries?
One strategy that is consistent with your access pattern is to add a new indexed column "first_letter" to your table. Use a trigger on to set the value on insert and update. Then your query is a simple group by first_letter.
Another strategy is to create a shadow table which contains an aggregation of the mother table. This isn't easy because it is your job as developer to keep the shadow table consistent with the mother table. Every delete, update or insert in table files needs to be accompanied by a change in the shadow table.
Databases like Oracle have support for materialized views to achieve this automatically but sqlite doesn't.