BISM Archives - BI Insight

The terms “DirectQuery” and “Connect Live” are somehow confusing. I saw lots of people are using both terminologies as alternatives. But, the context of “DirectQuery” and “Connect Live” are very different indeed. Therefore, if use a a terminology when we’re talking about a different context then the whole situation might get quite confusing. in this post I try to explain the differences and make it more clear to prevent using a wrong terminology and make sure everyone is on the same page when we’re referring to “DirectQuery” or “Connect Live”.

When we use the “DirectQuery” terminology we are actually talking about connecting from Power BI Desktop instance to an RDBMS type of data source like SQL Server DB or Oracle DB.

There are two types of data connections when we’re connecting to RDBMS like SQL Server or Oracle DB from Power BI Desktop:

Import Data: which literally loads data into the underlying model to make it available in memory
DirectQuery: which doesn’t load data into model. Instead, it runs multiple concurrent queries on the RDBMS side (data source side) and gets the results. This is good to support real-time data processing.

Note: The same principal applies to SSAS Tabular.

On the other hand, when talk about “Connect Live”, we are referring to the data connection type from a reporting tool like Power BI Desktop OR Excel to an instance of SSAS, either SSAS Multidimensional or SSAS Tabular.

Continue reading “Demystifying “DirectQuery” and “Connect Live”” →

SSAS 2012 supports three different approaches for creating a BISM (Business Intelligence Semantic Model):

1. Tabular

a. Uses relational modelling constructs like such as tables and relationships

b. Uses xVelocity in-memory analytics engine for sorting and data calculations

c. Needs to use SSDT (SQL Server Data Tools) to implement

d. Can import data from relational data sources using OLE DB native and managed providers

e. Tabular solutions only support one model.bim file per solution, which means that all work must be done in a single file. Development teams that are accustomed to working with multiple projects in a single solution might need to revise how they work when building a shared tabular solution.

f. support DAX calculations, DAX queries, and MDX queries

g. Tabular model databases can use row-level security, using role-based permissions in Analysis Services (DAX implementation required)

h. It might be not a good choice for the systems that are going to load terabytes of data

Continue reading “Three different approaches for creating a BISM in SSAS 2012, Tabular vs. Multidimensional vs. PowerPivot” →