---
title: "Dax@1"
description: "Dax@1 (legacy) — tabular models in Power BI and SQL Server Analysis Services, queried in DAX through the MSOLAP OLE DB driver"
url: "https://docs.justcat.it/reference/data-sources/providers/dax-1/"
---
# Dax@1


> **😾:** **Deprecated.** `Dax@1` still works, but it is no longer maintained and gets no new features. Use [Dax@2](https://docs.justcat.it/reference/data-sources/providers/dax-2/ "Dax@2") instead — the same DAX queries, no driver to install.



## Connects to

Local or remote tabular models in SSAS and Power BI: Power BI Semantic Model, SQL Server Analysis Services. Legacy providers have no technology of their own — use the technology of the replacement, `Dax@2`.

## Example


**Properties**



Name
: My Power BI Dataset

Provider
: Dax@1

Technology
: PowerBISemanticModel

Connection string
: ```
  Provider=MSOLAP;
  Data Source=powerbi://api.powerbi.com/v1.0/your-organization.com/your-workspace-name;
  Initial Catalog=Your-Dataset-Name;
  User ID=%YOUR_SERVICE_PRINCIPAL_NAME_ENVIRONMENT_VARIABLE_NAME%;
  Password=%YOUR_SERVICE_PRINCIPAL_SECRET_ENVIRONMENT_VARIABLE_NAME%;
  ```





**YAML**


```yaml
Data sources:
- Name: My Power BI Dataset
  Provider: Dax@1
  Technology: PowerBISemanticModel
  Connection string: >
    Provider=MSOLAP;
    Data Source=powerbi://api.powerbi.com/v1.0/your-organization.com/your-workspace-name;
    Initial Catalog=Your-Dataset-Name;
    User ID=%YOUR_SERVICE_PRINCIPAL_NAME_ENVIRONMENT_VARIABLE_NAME%;
    Password=%YOUR_SERVICE_PRINCIPAL_SECRET_ENVIRONMENT_VARIABLE_NAME%;
```




Replace the placeholders (your-organization.com, your-workspace-name and your-dataset-name) with real values.

## Connection string

An OLE DB connection string for the MSOLAP provider — `Key=Value` pairs separated by semicolons. The keys you will use most:

| Key | Meaning |
|---|---|
| `Provider` | Always `MSOLAP` |
| `Data Source` | IP address or name of your server; for a workspace `powerbi://api.powerbi.com/v1.0/<organization>/<workspace>` |
| `Initial Catalog`, `Catalog` | Name of the database (dataset) you want to run queries against |
| `User ID`, `Password` | Service principal name and secret |
| `Integrated Security` | `SSPI` for local connections to SSAS |

The full list is in the <a href="https://learn.microsoft.com/en-us/analysis-services/instances/connection-string-properties-analysis-services" target="_blank">Analysis Services connection string reference</a>.

A password, or the whole string, can come from an environment variable — `%NAME%` is replaced with the value of `NAME`; see [How every provider is used](https://docs.justcat.it/reference/data-sources/providers/introduction/#how-every-provider-is-used "How every provider is used").

### Power BI workspace

**You must have Power BI Premium or Power BI Premium per user** in order to connect to a Power BI dataset programmatically. You already must have a service principal with a valid secret and with admin access to your Power BI workspace — the example above.

Both ways of testing Power BI data — on your machine and in a Power BI workspace — are walked through in [Test Power BI](https://docs.justcat.it/how-to-guides/data-platforms/power-bi/test-power-bi/ "Test Power BI").

### SSAS


**Properties**



Name
: My Tabular Model

Provider
: Dax@1

Technology
: Ssas

Connection string
: ```
  Provider=MSOLAP;
  data source=localhost;
  integrated security=SSPI;
  Catalog=WideWorldImporters;
  ```





**YAML**


```yaml
Data sources:
- Name: My Tabular Model
  Provider: Dax@1
  Technology: Ssas
  Connection string: >
    Provider=MSOLAP;
    data source=localhost;
    integrated security=SSPI;
    Catalog=WideWorldImporters;
```




## Settings

None beyond `Connection string`.

## Query

Tabular models do not understand SQL. The statement is one <a href="https://learn.microsoft.com/en-us/dax/" target="_blank">DAX</a> query — **knowledge of at least the very basics of DAX is required**.

A test comparing the data a DAX query returns (a made-up example without much sense) with expected data provided in YAML:

```yaml
Tests:
- Name: Check zip codes
  First Data Source: MyTabularModel
  First Query: |
    EVALUATE(
    	TOPN(3,VALUES('Customer'[Postal Code]))
    )
    ORDER BY 'Customer'[Postal Code]
  Second data source: yaml
  Second Query: /Expected results
  Expectation: sets match
```

## Prerequisites

The MSOLAP driver from Microsoft: <a href="https://learn.microsoft.com/en-us/analysis-services/client-libraries?view=asallproducts-allversions#windows-installer" target="_blank">https://learn.microsoft.com/en-us/analysis-services/client-libraries?view=asallproducts-allversions#windows-installer</a>. Download and install **MSOLAP (amd64)**:

![MS OLAP driver](ms-olap-driver.png)

The link leads to an `.msi` file; install it with Next, Next, Next… Windows only.

## Limitations

* Windows only — the MSOLAP OLE DB driver has no Linux build.
* Cannot serve lists of definitions — DAX returns column names in square brackets (`Tests[Test name]`, `[Test name]`), which CAT does not match to property names.

## Serving test and data source definitions

`Dax@1` cannot serve [lists](https://docs.justcat.it/reference/project-file/lists/ "Lists") of definitions. A DAX query returns its column names in square brackets — `Tests[Test name]` for a model column, `[Test name]` for a column the query names itself — and CAT matches definition properties by name, brackets included: `[Test name]` is not `Test name`.

## Related

* [Dax@2](https://docs.justcat.it/reference/data-sources/providers/dax-2/ "Dax@2") — the replacement; the same DAX queries, no driver to install.
* [Technologies](https://docs.justcat.it/reference/data-sources/technologies/ "Technologies").
* [Test Power BI](https://docs.justcat.it/how-to-guides/data-platforms/power-bi/test-power-bi/ "Test Power BI").