如何用Oracle DW创建OLAP Cube？SSAS连接Oracle DW建Cube等技术咨询

Hey there, let's break down your questions about OLAP cubes with Oracle DW and SSAS one by one—happy to help you get up to speed!

Oracle OLAP is tightly integrated with Oracle Data Warehouse, and you have two main paths to build a cube:

• Using Oracle Analytic Workspace Manager (AWM) (GUI tool):
  • First, make sure your Oracle DW has a properly designed star/snowflake schema (dimension tables + fact tables) with clean, consistent data.
  • Install and launch AWM, then connect to your Oracle DW instance. Create an Analytic Workspace (AW)—this is the container for your cube.
  • Define dimensions: Map your dimension tables to OLAP dimension objects, set up hierarchies (e.g., Year → Quarter → Month) and attributes (like "Region Name" for a geography dimension).
  • Build the cube: Link your fact table to the dimensions, select the measures you want to aggregate (e.g., sales amount, unit count), and configure aggregation rules (SUM, AVG, COUNT, etc.).
  • Load and refresh data: Use AWM's load wizard or PL/SQL packages like DBMS_AWM to populate the cube with data from your DW.
• Using PL/SQL/DDL (command-line approach, ideal for automation):
  • For Oracle 12c+, you can use simplified DDL statements like CREATE CUBE and CREATE DIMENSION to define your OLAP objects directly in SQL. For example:

    CREATE DIMENSION time_dim
      LEVEL year IS time.year_id
      LEVEL quarter IS time.quarter_id
      LEVEL month IS time.month_id
      HIERARCHY time_hier (month CHILD OF quarter CHILD OF year);
    

  • Use DBMS_OLAP packages to manage data loading and aggregation.

You can also use Oracle SQL Developer with the OLAP extension enabled to streamline these steps.

Absolutely! SSAS (SQL Server Analysis Services) supports Oracle as a native data source. Here's how to do it:

• Open SQL Server Data Tools (SSDT) and create a new SSAS Multidimensional or Tabular project.
• Configure a data source: Select "Oracle" as the source type, then enter your Oracle DW connection details (server name, port, SID/service name, credentials). Note: You'll need the Oracle Data Access Components (ODAC) driver installed on your machine/SSAS server to enable this connection.
• Build a Data Source View (DSV): Import your Oracle DW's dimension and fact tables, then define relationships between them to mirror your star/snowflake schema.
• Create dimensions: Use the DSV to build OLAP dimensions, set up hierarchies, and define attributes.
• Build the cube: Run the Cube Wizard, select your fact table and measures, link them to the dimensions you created, and set aggregation options.
• Deploy the cube to your SSAS server, then query it using tools like Excel, Power BI, or SSRS.

It all depends on your existing tech stack and business needs:

• Choose SSAS if:
  • Your environment is heavily invested in Microsoft technologies (SQL Server, Power BI, Excel, Azure). SSAS integrates seamlessly with these tools, and the learning curve is gentler for teams familiar with Microsoft's ecosystem.
  • You prefer lightweight, modern Tabular models (great for self-service BI and large-scale data) over traditional multidimensional cubes.
• Choose Oracle OLAP if:
  • You're running a full Oracle stack (Oracle DB, Oracle BIEE, EBS, etc.). It's deeply optimized for Oracle databases, offers advanced OLAP calculations, and can be managed directly within your Oracle DW without extra server infrastructure.
  • You need extreme performance for massive datasets, especially when paired with Oracle Exadata.

Also, keep in mind: SSAS's multidimensional model is being phased out in favor of Tabular, while Oracle OLAP remains focused on traditional multidimensional cube use cases.

Oracle OLAP Requirements #

• Database: Oracle Database Enterprise Edition (Standard Edition doesn't include the OLAP option). We recommend 11g R2 or later, with 12c+ for simplified DDL support.
• Permissions: Your user needs roles like OLAP_DBA or OLAP_USER, plus read/write access to your dimension and fact tables.
• Tools: Analytic Workspace Manager (AWM), Oracle SQL Developer (with OLAP extension), or PL/SQL development skills for automation.
• Resources: Sufficient memory and storage—pre-aggregated cube data requires dedicated space, and OLAP operations are memory-intensive.

SSAS Requirements #

• Server: A machine running SQL Server Analysis Services (can be installed alongside SQL Server or as a standalone instance). We recommend 2016+ for Tabular model support.
• Development Tools: SQL Server Data Tools (SSDT) or Visual Studio with the Analysis Services extension.
• Drivers: Oracle ODAC driver (matching the bitness of your SSAS server) to connect to Oracle DW.
• Permissions: SSAS server admin rights (for deploying cubes), read/write access to Oracle DW, and client tool access permissions.
• Resources: SSAS is memory-heavy, especially for MOLAP cubes—ensure your server has enough RAM to load cube data efficiently.

Oracle OLAP Tools Installation #

• Analytic Workspace Manager (AWM): Download the version matching your Oracle DB from Oracle's official site. Run the installer, follow the prompts, and configure your database connection after installation.
• Oracle SQL Developer: Download the free tool from Oracle's site. After installation, go to Tools > Features and enable the OLAP extension, then restart the app to access OLAP functionality.
• Enable OLAP Option in Oracle DB: If you didn't enable OLAP during database installation, use the Database Configuration Assistant (DBCA) to modify your instance and turn on the OLAP option.

SSAS Tools Installation #

• SQL Server Analysis Services: Run the SQL Server installer, select the "Analysis Services" role, then choose your preferred mode (Multidimensional and Data Mining, or Tabular).
• SQL Server Data Tools (SSDT): Install via the Visual Studio Marketplace, or select the "Data storage and processing" workload when installing Visual Studio 2019/2022.
• Oracle ODAC Driver: Download the appropriate bitness package (e.g., ODAC 12c Release 4) from Oracle's site. During installation, select "Oracle Data Provider for .NET" and "Oracle Provider for OLE DB" to enable SSAS connectivity.

内容的提问来源于stack exchange，提问作者Durai Murugan