I am trying to create one-to-one relationships between the a User and Archive table. I successfully achieved that using entity relationship diagram, but not in actual SQL code.
I wan to create these tables using SQL code like shown below, but at the same time defining its relationship with Table 2.
CREATE TABLE Table1
(
Some code
);
Related
I'm new to Azure and not great with SQL so any help would be greatly appreciated.
I have a Database where each user has a Schema. Each Schema has identically structured tables with the same name, say "Table".
I now require a View in another Schema which provides a read-only union of all the rows from all the tables Table.
I was successful in creating a Schema, say Views, handling its permissions and creating a View, "TableView", with the following SQL from Partitioned Views # learn.microsoft.com:
CREATE VIEW Views.TableView
AS
SELECT *
FROM Schema1.Table
UNION ALL
SELECT *
FROM Schema2.Table
UNION ALL
SELECT *
FROM Schema3.Table
...
GO
I now wish for this View to be dynamic as future Schemas (SchemaX) are added or even possibly removed without having to repeatedly DROP and CREATE TableView over and over.
Is it possible to create the View in such a way that it would automatically query all tables with the same name? Or perhaps there is some way to 'add' an additional table post creation?
I can get a list of all SchemaX.Table by querying INFORMATION_SCHEMA, but other than having a python script DROP and CREATE the View again I am lost.
Thanks
Thanks for #larnu's comments, it's very useful and professional:
To achieve this dynamically, it would be impossible to do in a VIEW.
You would have to use a stored procedure, and that means you can't do
simple things like SELECT from it, making it far harder to use.
Instead of having 17 tables, all identical, on different schemas you
have one table, with a column BusinessName. Instead of
MySmartCompany.Mytable you have a column in the table dbo.MyTable (or
your generic schema), called BusinessName which has the value 'MySmartCompany'.
This also can be beneficial to other community members.
I try to drop my tables in Apache ignite.
For example;
drop table if exists city
The code is working for PUBLIC schema but I couldn't delete tables from other schemas.
The error says 'Failed to parse query. Table "PRODUCT" not found;'
Here is the screenshot of my PowerShell?
How can I delete the tables belong the different schemas?
You need to fully qualify it:
drop table "Product".PRODUCT;
You need to do the same thing whenever you reference tables in different schemas, for example with a JOIN.
I have a table called Table 1. I'm trying to create an after-insert trigger for a Table 1; whereby, whenever a user enters a record, the trigger will create a new table named after the record that triggered its creation.
Please help, I'm using SQL Server 2008
This sounds super non-relational-database-design-ish. I would heavily advise against this in almost every case. And I say "almost" only to allow for artistic freedom of development, I can't think of a single case where this would be appropriate.
That said, if you do in fact want this, you can use dynamic SQL to create a table.
You can build the SQL in your trigger, but basically you want something like:
EXEC 'CREATE TABLE ' + #tableName + ' (ID INT IDENTITY(1,1))';
Of course, the columns are up to you, but that should get you started.
But while we're at it, what you should (probably) be doing is using a single table with a one-to-many relationship to the table on which your trigger is currently assigned.
For instance, if you have a table Users with a column for email and you're looking to create a table for each user's favorites on your website, you should instead consider adding an identity column for user IDs, then reference that in a single UserFavorites table that has UserId and PostId columns, and the appropriate foreign keys implemented.
I have a distributed data base with two nodes. I have a table like this one in node2 (only in this node):
CREATE TABLE table2
(
cod_proveedor CHAR(15) REFERENCES proveedor(cod_proveedor),
cod_articulo CHAR(15) REFERENCES articulo(cod_articulo),
);
Now, I have the tables "articulo" in node1 and node2.
As we see, I am doing REFERENCES to nodo2.proveedor and nodo2.articulo because my table "table2" is in this node "node2".
I gotta do reference to nodo1.proveedor when I am creating the table but I don't know how...
Can you help me?
If "distributed database" means that you have two separate databases, you cannot create foreign key constraints in one database that references a table in another database.
You could create a materialized view in database 2 that pulls all the proveedor data from database 1 to database 2 and then create a foreign key constraint in database 2 that references the materialized view. Of course, since there would be a lag between when new data was written to the table on database 1 and when the materialized view was updated on database 2 that you could have windows where a child row couldn't be written despite the parent row existing on database 1. And if you deleted a row in database 1, you wouldn't find out whether there were child rows that would be orphaned until you tried to replicate that change to database 2. You'll need to write a lot of code to detect and to resolve these sorts of errors.
In Oracle, it would generally make far more sense to create a single database using RAC (Real Application Clusters) that is mounted on multiple physical servers. That would allow you to distribute the load across the database servers where each server has access to the full contents of the database rather than distributing subsets of data to different nodes.
Situation:
I have quite a few tables created in SQL
These tables are linked to MS Access
I can very easily "add" new entries to all but one of the tables
This table includes a Foreign key reference (but so do others)
All tables are created the same way and linked the same way
Problem:
I cannot add entries in the Spreadsheet View in Access. Generally you have some sort of entry like (where there is a * as well as empty row beneath the table you can click in and begin typing)
However this table looks like:
Right clicking on a record has "New Record" and "Delete Record" grayed out, while I can use this on other tables
I am creating the table using:
CREATE TABLE ProjectApprovers (
ProjectCode varchar(50) FOREIGN KEY REFERENCES ProjectCodes(ProjectCode),
RACFApprover varchar(50)
);
The reason I am confused is that it does not appear to be a SQL permissions problem because I can run the following code in Access:
INSERT INTO ProjectApprovers (ProjectCode,RACFApprover) VALUES ('ValidProjectCode','test123');
It seems these restrictions are only limited to the spreadsheet view. Additionally, identical syntax is used to create other tables which do not have this problem.
I am using this code to link my database tables.
Is something like this a permission problem? I have never referenced this problem table with permissions.
If Access doesn't recognize a primary key in the linked table, it will present the table as read-only in Datasheet View.
Fix this by adding a primary key in SQL Server. Then recreate the link in Access so it can notice the changed table structure.