Solved: How to create a specific type of relationship - Microsoft Power BI Community
What Do Ephemeral Computing and Autoscaling Bring to the SaaS Industry? . Flat databases are also sometimes referred to as flat-file databases. databases , flat databases cannot represent complex relationships between entities. and indexes cannot be created because the data is all lumped together in one table. Presumably, the CSV file is an export to another system, or just to somebody who I can get one case with a left outter join but can't find a creative way to get to. The check value can drop to only one of these or it can drop to multiple territories. I don't have the option of modifying this flat file, so is there some way to do this . pulled both files via get data (excel) into power BI and created a relationship.
Flat files can be created in relational database engines by not taking advantage of relational design concepts. Designing a relational database takes more planning than flat file databases.
With flat files, you may add information, as you deem necessary. With relational databases, you must be careful to store data in tables such that the relationships make sense. Building a relational database is dependant upon your ability to establish a relational model.
The model must fully describe how the data is organized, in terms of data structure, integrity, querying, manipulation and storage. Relational databases allow you to define certain record fields, as keys or indexes, to perform search queries, join table records and establish integrity constraints.
Search queries are faster and more accurate when based on indexed values. Table records can be easily joined by the indexed values. Integrity constraints can be established to ensure that table relationships are valid. If you are able to establish a one-to-many relationship in your data tables, you should be using a relational database because a flat file is not sufficient to handle your data processing needs. Relational databases offer more robust reporting with report generators that filter and display selected fields.
Relational databases offer the capability to build your own reporting modules. Most relational databases also offer the capability to import and export data from other software. There are three primary relational database systems, proprietary, open source and embedded.
Relationships between flat file record formats
Proprietary relational databases require the use of proprietary development languages, often times, to complement SQL. Open source databases, such as MySQL, are distributed freely to encourage user development. Like with the closest feature or features association above, you can append either the attributes of a single intersecting feature or an aggregate of the numeric attributes of the intersecting features.
For each point, polygon, and line combination, only the most commonly used of these associations are available in the join dialog box. With VBA, however, it is possible to perform a join based on any association and with any combination of point, line, or polygon feature layers. Relating tables Unlike joining tables, relating tables simply defines a relationship between two tables. The associated data isn't appended to the layer's attribute table like it is with a join.
Instead, you can access the related data when you work with the layer's attributes. For example, if you select a building, you can find all the tenants that occupy that building.
Similarly, if you select a tenant, you can find what building it resides in or several buildings, in the case of a chain of stores in multiple shopping centers—a many-to-many relationship.
However, if you performed a join on such data, ArcMap will only find the first tenant belonging to each building, ignoring additional tenants.
Relates defined in ArcMap are essentially the same as simple relationship classes defined in a geodatabase, except that they are saved with the map instead of in a geodatabase. If your data is stored in a geodatabase and has relationship classes defined, you can use these directly without having to establish a relate in ArcMap. The relationship classes will automatically be available when you add a layer that participates in a relationship class to the map.
Note that the many-to-many relationship is defined differently when your data is stored in a geodatabase. In general, if you have relationship classes defined in your geodatabase, you should use these instead of creating new ones in ArcMap. Learn how to create a relationship class Relationship classes in the geodatabase A relationship class stores information about associations among features and records in a geodatabase and can help ensure your data's integrity.
Joins versus relates Follow these general guidelines when choosing between joins and relates on your data: You'll want to join two tables when the data in the tables has a one-to-one or a many-to-one relationship.
You'll want to relate two tables when the data in the tables has a one-to-many or many-to-many relationship. Learn more about deciding between relationship classes, joins, and relates Saving joins and relates When you save a map containing joins and relates, ArcMap saves the definition of how the two attribute tables are linked rather than saving the linked data itself.
BBC Bitesize - GCSE Computer Science - Relational databases - Revision 1
The next time you open your map, ArcMap reestablishes the relationship whether a join or relate between the tables by reading the tables from the database. In this way, any changes to the source tables that have taken place since they were last viewed on the map are automatically included and reflected on the map.
Joins can be stored in an ArcMap document or in a layer file. If you plan on moving the data at some point, you should save your ArcMap documents with relative paths. If data is moved, you can repair tables and layers after opening the document, but unless the target table and the join tables are in the same directory or workspace, the joins are not repaired.
If you save your document with relative paths, tables and layers are restored automatically with joins as long as the document has been moved relative to where the data has been moved. You can make a permanent disk copy of a layer with joined data simply by exporting the layer.
To export the layer, right-click it in the table of contents, point to Data, then click Export Data. This creates a new feature class with all the attributes, including the joined fields. Using joins, relates, and relationship classes together If your data is involved in both joins and relates, the order in which the joins and relates are created is significant. If your layer or table has a relate, it is removed once data is joined to it.
If you perform a relate on a joined layer or table, the relate is removed when the join is removed.
As a general rule of thumb, it is best to create your joins, then add your relates. In a situation where you need to join tableA and relate tableB to layerC, two of the three possible ways of doing this will work.
The following describes each case: Join tableA to layerC, then relate tableB to layerC: You end up with a joined layer that has a relate to tableB. Relate layerC to tableB, then join tableA to layerC: This scenario also works.
Since a relate is bidirectional, both tables involved are able to use it regardless of which table owns the relate. In this case, tableB owns the relate, so when tableA is joined to layerC, the relate is not removed.
Relate tableB to layerC, then join tableA to layerC: This scenario does not work. This is different from the previous scenario in that layerC owns the relate. Therefore, when tableA is joined to layerC, the relate is removed.
Relates owned by the join table are not affected by the join. These relates can't be accessed by the target table or layer, however. Relationship classes are never removed as a result of a join or unjoin operation.