I am using Teradata via Sql Assistant. When I want to look up a relationship between two table I do the following : show table table1 and can see the create statement that generated the table with all primary and foreign keys. However, this is not very convenient because I might be missing something. So, is there any way to get the Entity Relationship Diagram ? I am interested in about 20 tables. So, how can I get relationships between them ?
SQL Assistant does not show relationships between objects through version 14.x. In my experience with Teradata, relationships have been modeled in proper modeling tools.
If your environment is enforcing referential integrity there are views in the DBC database that could be queried in SQL Assistant to help show you the relationships. However, the results would be in tabular form like any other query against the database.
DBC.All_RI_Children
DBC.All_RI_Parents
DBC.RI_Child_Tables
DBC.RI_Distinct_Children
DBC.RI_Distinct_Parents
DBC.RI_Parent_Tables
DBC.Tables2
Related
I want to create a sqlite database with at least two tables: account and service. One account can have several services and one service can be used by several accounts.
I would like to be able to query all the services which one account uses.
Now, where it gets complicated for me is that I would like to avoid a third table which is usually used - as far as I know - to resolve this many-to-many relationship.
Is there an appropriate way to do this?
Thank you!
You can denormalize your schema and store relations in a field containing an array in each table. But this is going to be less efficient to query and not all database engines support array type. Actually sqlite3 doesn't. You can mitigate that by storing that as a JSON data type which will be then an array in JSON representation.
I want a query to get the column relation or reference of column for the table or for all the databases.
Like in MySQL, we have a query
SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE
TABLE_SCHEMA = 'database_name';
So, What is the query for Progress OpenEdge to get column relation.
Also where are procedure, functions and views stored in ProgressDB?
Query to view database name list?
To find relationships, or views, or stored procedures you must query the meta-schema. Stefan's link documents SYSTABLES, SYSCOLUMNS, SYSINDEXES, SYSPROCEDURES, and SYSVIEWS. These are the tables that define what you have asked for.
https://docs.progress.com/bundle/openedge-sql-reference-117/page/OpenEdge-SQL-System-Catalog-Tables.html
The Progress database does not explicitly store relationships. They are implied, by convention, when there are common field names between tables but this does not create any special relationship in the engine. You can parse the tables above and make some guesses but, ultimately, you probably need to refer to the documentation for the application that you are working with.
Most Progress databases were created to be used by Progress 4gl applications. SQL came later and is mostly used to support 3rd party reporting tools. As a result there are two personas - the 4gl and sql. They have have many common capabilities but there are some things that they do not share. Stored procedures are one such feature. You can create them on the sql side but the 4gl side of things does not know about them and and will not use them to enforce constraints or for any other purpose. Since, as I mentioned, most Progress databases are created to support a 4gl application, it is very unusual to have any sql stored procedures.
(To make matters even more complicated there is some old sql-89 syntax embedded within the 4gl engine. But this very old syntax is really just token sql support and is not available to non-4gl programs.)
I am new to cosmos db. I chose cosmos db (core sql), created a database having two containers say EmployeeContainer and DepartmentContainer. Now I want to query these two container and want to fetch employee details with associated department details. I stuck on a point and need help.
Below is the structure of my containers.
EmployeeContainer : ID, Name, DepartmentID
DepartmentContainer: ID, Name
Thanks in advance.
Cosmos DB is not a relational database. You do not store different entities in different containers if they are queried together. They are either embedded in other entities or stored as separate rows using a shared partition key with other entities in the same container.
Before you get too far with Cosmos you need to understand how to model and partition data to ensure the best possible performance. I strongly recommend you read the docs on partitioning and specifically read these docs below.
Data modeling in Cosmos DB
Partitioning in Cosmos DB
How to model and partition data - a real world example
And watch Data Modeling in Cosmos DB - What every relational developer should know
It completely depends on the type of data you are trying to model. Generally, it comes down to relationships. 1:1 or 1:few often are best for embedding related items or where queries are updated together. 1:many or many:many for referencing related items are queried or updated independently.
For great talks on these issues check out https://www.gotcosmos.com/conf/ondemand
You can use subquery.
https://learn.microsoft.com/en-us/azure/cosmos-db/sql-query-subquery#mimic-join-with-external-reference-data
But this may consumes a lot of RU. And only inner join for now.
I have created a connection to the database in a SQL developer. Now in there I can see lots of Table having different dependencies and constraints applied. now its very confusing and time consuming to see the details of each table manually. I want them in a way(GUI) so that I can easily Identify that particular table is master one and all the dependencies of all other tables. does it provide any kind of tool ? or is there any other Method ?
You can generate an ER diagram for the objects and their relations.
File -> Data Modeler -> Import -> Data Dictionary
Choose the database and schema which contains the objects.
Choose the objects
I went through a custom profile provider example a while ago and I am
now revisiting it.
My database has all the dbo.aspnet_* tables created when I ran the aspnet registration
wizard. In these tables I have aspnet_Profile which has a FK constraint pointing to aspnet_Users.
I also have two tables in MyDB: The first, dbo.ProfileData, has a foreign key constraint
pointing to dbo.Profile.
What I want to understand is how the tables in MyDB relate to
those in dbo.aspnet_*. Shouldn't there be a foreign key constraint (or some kind of
relationship) between the profile tables in MyDB and the aspnet tables? Some discussion
of how my custom tables relate to those provided by aspnet would be wonderful.
Thanks in advance.
There are two options I can see, both of which will yield basically the same result:
FK from dbo.aspnet_User.UserID to dbo.Profile.UserID, then define a unique key on dbo.Profile.UserID (unless you use it as the PK column for dbo.Profile)
FK from dbo.aspnet_Profile.ProfileID to dbo.Profile.ProfileID
dbo.aspnet_User is logically 1 - 1 with dbo.aspnet_Profile, so it doesn't really matter which approach you use as you will still get the same relational integrity.
If you are replacing the standard profile data table with your own implementation then it makes more sense to use the first suggestion, otherwise if you are extending the Profile schema then use the second suggestion.
EDIT
aspnet_Profile is the standard table - the standard SqlProfileProvider stores the user's profile data as a serialized property bag in aspnet_Profile, hence why there is no separate aspnet_ProfileData table as well.
This approach allows the profile schema to be customized easily for different applications without requiring any changes to the underlying database, and is the most optimal solution for a framework such as .NET. The drawback is that SQL Server does not have easy access to this data at all, so it is much more difficult to index, update and query the user's profile data using T-SQL and set-based logic.
The most common approach I have seen to remove this limitation is to extend the standard SqlProfileProvider to write to a custom profile data table which has specific columns for application-specific profile properties. This table naturally has a 1-1 relationship with the aspnet_Profile table, so it has a foreign key as indicated above.
The role of the extended provider is to promote specific profile properties to columns during profile writes, and read in the columns when the profile is retrieved.
This allows you to mix-and-match storage solutions on an as-needs basis, as long as your extended provider knows how to fall back to the standard implementation where it does not 'know' about a given property.
I always think it is best to leave the standard membership tables as-is, and extend where necessary using new tables with appropriate foreign keys, then subclass the appropriate provider and override the provider methods with your own implementation (calling into the base implementation wherever possible).