I am developing a windows application and using Postgres as backend database. At some point in my application i am dynamically creating table e.g Table1, then Table2 and so on. In this way i have many dynamic table in my database. Now i provide a button "Clean Database", so i need to remove all those dynamic tables using SQL query. Should some one guide me how to write SQL Query that automatically delete all such tables?
You should just be able to say
DROP TABLE {tablename}
for each dynamically created table. Try that and see if it works.
Related
I have an Access query, which references a table: dbo_table2
However, I have moved this table to another database, so I need to fully qualify to restore the links.
SELECT table1.x, table1.y, table2.z
FROM dbo_table1
INNER JOIN dbo_table2
ON (dbo_ID = dbo_ID)
Both tables are being pulled from SQL tables.
In my Access query I have added table2 as a Linked Table.
But I'm unsure of Access syntax. If I was using SQL, I would simply use "newdatabaseDB.dbo.table2".
My question is how can I correctly name the table2 reference by fully qualifying the database and table name.
If you moved your table to another db, just Link that table in your current db. This way you can use just as it was local.
There is another option, using IN:
select * from clients in 'c:\test\mydb.mdb'
Also see https://stackoverflow.com/a/3123395/78522
Cracked it!
By creating a link to an external table in the database where the query was created, Access then treats the table in the queries as if it were local (so no fully qualification needed).
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));
In the begining I have given service broker enable status to database on MSSQL 2008. I have two tables with same fields. First one is existing table. Other is created new by me. Hub is not working with first existing table, but works fine with other table which we create new.
Our select statement is basic and we have used only select field like 'select field1,field2 from Table1 where field2=1'.
I am using C#.
What kind of problem can be in this issue, how can we solve?
I have found solution. SignalR wants table scheame name in sql statement. Default scheme name is dbo and our sql or stored procedure include dbo. Like:
'Select field1,field2 from dbo.Table1 where field2=1'.
I have two schemas in my Postgres BOOK database, MSPRESS and ORELLY.
I want to create the same table in two schemas:
CREATE TABLE MSPRRESS.BOOK(title TEXT, author TEXT);
CREATE TABLE ORELLY.BOOK(title TEXT, author TEXT);
Now, I want to create the same table in all my schemas with a single command.
To accomplish this, I thought about event triggers available in Postgres 9.3 (http://www.postgresql.org/docs/9.3/static/event-triggers.html). Intercepting CREATE TABLE command by my event trigger, I thought to determine name of table and schema in which it is created and just repeat the same command for all available schemas. Sadly, event trigger procedure does not get name of table being created.
Is there a way to 'real-time' synchronization of Postgres schema?
Currently only TG_EVENT and TG_TAG is available from an event trigger, but this feature will likely be expanded. In the meantime, you can query information_schema for differences and try to add every table, where its missing; but don't forget that this synchronization will also trigger several event triggers, so you should do it carefully.
But if you just want to build several schemas with the same structure (without further synchronization), you could just write schema-less queries to build them & run it on every schema one-by-one, after changing search path with SET search_path / SET SCHEMA.
I am using Eclipse, Java and a Derby database. I want to experiment with changing values that rewrite one of the tables in the db. Before starting the change I would like to copy the particular table (not in code) so that I can restore the original data if necessary. Sof ar googling and searching this site hasnt produced an answer. In Eclipse there is an option to export the db but it calls it a connection so I am not usre what would happen.
If you're not sure about how to connect to the database and issue sql statements, you will need to learn about JDBC. This is a good place to start.
If you're asking about the SQL, it's pretty straight forward. You can create a table based on a select statement.
e.g.
create table table2 as select * from table1 with no data;
Derby is a little strange in this area. You must specify the with no data, and the created table will be empty. You can then issue an insert that will populate the new table if you wish.
insert into table2 select * from table1;
The new table will not have indexes. You will need to create them if you want them. It might retain the primary key. You should check that if you're testing against it. If it doesn't retain the primary key, you should create the primary key before inserting data into the table.
In Eclipse there is an option to export the db but it calls it a connection so I am not sure what would happen.
If what Eclipse does isn't clear for you, you can just as well zip your entire database directory (content of DERBY_HOME env. variable) into an archive. The database must not be running while you make the backup.