Migrating databases from Oracle to Microsoft SQL Server can be a complex endeavor, especially when it comes to dealing with differences in schema structures, data types, and specific SQL clauses. The SQL Server Migration Assistant (SSMA) is a robust tool designed to automate these migrations and minimize manual effort. However, SSMA might not always produce optimal results, and understanding how to overcome these limitations is crucial for a successful migration.
At ABCloudz, we’ve encountered these challenges firsthand. Through our experience, we’ve learned that using native SQL Server functions can significantly enhance system efficiency. In this catalog post, we provide an overview of our in-depth blog posts that tackle the most common SSMA migration issues and offer solutions to ensure high performance and reliability throughout your database migration journey. Each article highlights a specific problem and provides practical tips and strategies for resolving it.
Error handling and unsupported SQL clauses
Oracle to SQL Server migration with SSMA: Converting interval expressions
This post explains how to handle Oracle’s INTERVAL data type expressions when using SQL Server Migration Assistant (SSMA). The post covers typical errors, such as O2SS0006, that occur due to unsupported data type mappings. It provides practical solutions, including updating column types and using custom SQL statements to ensure correct data migration.
Oracle to SQL Server migration with SSMA: Converting database links
This post addresses the challenges of converting Oracle database links to SQL Server using SQL Server Migration Assistant (SSMA). It covers the typical O2SS0563 error and explains why SSMA fails to automatically convert these links. The post offers practical solutions, such as using the OPENQUERY function or creating linked servers to maintain the functionality of database links.
Oracle to SQL Server migration with SSMA: Converting unsupported table expressions
This post addresses the O2SS0482 error that occurs when SQL Server Migration Assistant (SSMA) fails to convert Oracle table functions and nested table types. It explains why SSMA cannot handle certain Oracle expressions, such as TABLE() and user-defined types, and provides step-by-step instructions to manually adjust the code.
Data type conversions
Oracle to SQL Server migration with SSMA: Converting foreign keys with different types of columns and referenced columns
This post provides solutions for the O2SS0231 error that occurs when SQL Server Migration Assistant (SSMA) fails to convert Oracle foreign keys with different column data types. The article explains why SSMA cannot handle such foreign key relationships and outlines steps to manually adjust the column types to avoid data truncation and loss.
Use caution when mapping Oracle data types for procedures and function parameters in SSMA
This post highlights common challenges when using SQL Server Migration Assistant (SSMA) to map Oracle data types to SQL Server for procedures and function parameters. It discusses how SSMA’s default data type mappings, such as NUMBER to FLOAT(53) or VARCHAR2 to VARCHAR(max), can lead to compatibility issues with third-party applications and necessitate code modifications. The article provides best practices and recommendations for adjusting precision and length based on the source table columns, making it a must-read for those looking to optimize data type conversions during Oracle to SQL Server migration.
Oracle to SQL Server migration with SSMA: Converting interval literals
This post explains how to resolve the O2SS0086 error that occurs when SQL Server Migration Assistant (SSMA) fails to convert Oracle’s INTERVAL literals, such as DAY TO SECOND and YEAR TO MONTH. The article describes how to use the DATEADD function in SQL Server to replace unsupported Oracle interval literals. It includes code examples and practical recommendations for adjusting the syntax, making it easier for developers to manage time-based calculations during migration to SQL Server.
Performance optimization
Optimizing Date and Time Conversion in Oracle to SQL Server Migration
This post covers best practices for optimizing date and time conversions when migrating databases from Oracle to SQL Server using SQL Server Migration Assistant (SSMA). It explains how SSMA’s emulated functions, such as ssma_oracle.to_char_date and ssma_oracle.trunc_date, can result in slower performance and suggests using native SQL Server functions like FORMAT, CONVERT, DATEDIFF, and EOMONTH to improve efficiency.
Oracle to SQL Server migration with SSMA: Converting unparsed SQL — Pivot Operator
This post discusses how to resolve the O2SS0561 error that occurs when SQL Server Migration Assistant (SSMA) fails to convert Oracle’s PIVOT operator. The article explains step-by-step solutions for converting the PIVOT clause, such as using square brackets for pivot values, adding aliases, and modifying the SQL Server code to support multiple aggregates.
Oracle to SQL Server migration with SSMA: Converting materialized view with float type
This post explores how to handle the O2SS0522 error that occurs when SQL Server Migration Assistant (SSMA) fails to convert Oracle materialized views containing FLOAT data types. The article explains why SSMA cannot convert such views directly and provides a step-by-step guide to use memory-optimized tables and stored procedures to emulate Oracle’s behavior in SQL Server.
Architectural considerations
Schema mapping in migration from Oracle to SQL Server
This post discusses the challenges and best practices for schema mapping during Oracle to SQL Server migrations. It outlines key differences between Oracle’s architecture, where a database consists of multiple schemas, and SQL Server’s structure, where each database can contain several schemas. The article presents two primary schema mapping approaches—schema-to-database and schema-to-schema—explaining when to use each approach to maintain application logic and optimize performance.
Conclusion
If you’re planning a database migration from Oracle to SQL Server or already in the process, we highly recommend exploring each of these posts to gain a deeper understanding of the challenges and solutions associated with using SSMA. Bookmark this page for quick access to practical tips and guidelines, and don’t hesitate to reach out to us for guidance with your database migration projects. Our experts have successfully handled numerous migrations and can help you achieve a seamless transition.
