Why there is no foreign keys in Orchard CMS Database?
I mean, when to tables are linked by a column, why no foreign are created to shield the relation?
Related
I'm new to Azure synapse analytics and I'm trying to crate internal tables to create my DW.
I have just found out that we cannot use primary key/foreign key.
My question is, how do I relate my fact tables with my dimension tables? is it necessary to create any kind of relationship between them or just create it plainly and use joins whenever needed?
I suggest creating your tables with the primary key identified, it helps the optimiser make better query plan choices.
There is currently no syntax supported for foreign key identification.
As you suggested, just go ahead and write your joins.
Am currently creating a datawarehouse in Azure Synapse, however Synapse does not allow for the creation of foreign keys. This is vital for referential integrity between the fact and dimension table. Does anyone have any suggestions as to what the alternatives are in synapse to enforce a PK FK relationship?
I searched about this topic and I found that the focus of Synapse is performance and not integrity reinforcement. We can create primary keys and structure the star schema with fact, dimensions and code join tables between them.
It was confused me too until I make this tutorial and read this carefully.
Load Contoso retail data to Synapse SQL
In a star schema any referential integrity should be enforced within the ETL tool used to load the data and not in the DB itself.
Some DBs support logical FKs that can help with query execution plans but they should never be physicalised
I have Downloaded the Azure Cosmos DB Data Migration Tool from here.
i'm Migrating the Sql Data to Cosmos DB. while Using the Migration Tool.
Source Information
What Should i provide in the partition Key Field ?
In cosmosdb, The PartitionKey is a property that will exist on every single object that is best used to group similar objects together.
According to docs,
Specify the document property you wish to use as the Partition Key (if
Partition Key is left blank, documents are sharded randomly across the
target collections).
Collections over 10GB, partition key is required.
In order to understand more on PartionKey read here.
It depends if you migrating one table or multiple tables into a single collection?
I recommend using an Unique index that is exists in all the tables.
Alternately you can create a new partition key
I am following this article to create tables in Azure Mobile service as Easy tables in portal without using any Code or SQL server management studio.
But I don't find any option there to set the primary key or foreign key for a column.
Please suggest me some ways of doing it.
About Primary Key azure will create a Primary key automatically for you.
If you need a foreign key you should just connect to the SQL Azure that it creates for you and modify the tables in side the SQL Azure using TSQL.
In general if your DB structure is too complicated with a lot of relationships you should think of coding your own service as these easy tables as their name suggest are for "Easy" stuff to give you a boost start...
I am implementing offline capabilities to the store app using .NET backend Mobile Service with on-premise SQL server. In my SQL Server already have tables and data in it.
So, I added all the required models in to mobile service project and published the mobile service to azure. Also added all five system properties Id, CreatedAt, Deleted, UpdatedAt and Version to the existing tables in Database manually to enable database tables for offline capability.
But, My issue is one of the table already have a rowversion type column, So, when I tried to add Version column into the table it gives an error 'A table can have only one rowversion column',
My problem is I cannot rename the existing rowversion column to Version because the same db is using by other applications.
My question is can we use the existing rowversion column in place of Version?
Yes, you can use a different column name, just use Automapper to map your existing column to the Version property in ITableData.
Here's a sample that shows how to do it: https://github.com/paulbatum/FieldEngineerLite/tree/master/FieldEngineerLite.Service