Migrating from Microsoft SQL Server (MSSQL) to Oracle is a complex project that requires careful planning, schema conversion, data migration, and validation. Using tools like Oracle SQL Developer is the standard approach to automate much of this process. Phase 1: Assessment and Preparation
Analyze Source Data: Evaluate the MSSQL database for case sensitivity differences (SQL Server is usually case-insensitive, Oracle is case-sensitive).
Set Up Environment: Install Oracle SQL Developer and download the necessary JDBC drivers for SQL Server.
Create Migration Repository: In Oracle, create a dedicated user (e.g., mwrep) to store migration metadata.
Create Connections: Set up connections in SQL Developer for both the source (MSSQL) and target (Oracle) databases. Phase 2: Schema Conversion
Capture Source Model: Use the “Migration Wizard” in SQL Developer to capture the SQL Server database schema.
Convert to Oracle Model: Translate SQL Server objects (tables, views, stored procedures) into Oracle-compatible formats.
Generate Scripts: Create SQL scripts for creating the schema in the Oracle database.
Deploy Schema: Run the generated scripts to create database objects in the Oracle target. Phase 3: Data Migration
Configure Data Transfer: Choose between online (faster for small data) or offline (more reliable for large data) migration in the wizard.
Execute Data Load: Use the migration wizard to load data. The tool often utilizes Oracle’s sqlldr (SQL*Loader) to move data efficiently.
Verify Data: Perform row count checks and data type validation between the source and target. Phase 4: Post-Migration Adjustments
Recreate Sequences/Triggers: Replace SQL Server-specific auto-increment features with Oracle sequences and triggers.
Update SQL Syntax: Convert proprietary SQL Server T-SQL (e.g., GETDATE()) to Oracle PL/SQL (e.g., SYSDATE).
Update Applications: Update database connection strings, reports, and applications to use the new Oracle credentials and structures. Key Considerations
Case Sensitivity: MSSQL often treats abc123 and ABC123 as identical, while Oracle does not.
Data Types: Ensure mapping is accurate (e.g., DATETIME vs. TIMESTAMP).
Encrypted Data: Specialized handling is required to move encrypted columns, as they may not migrate directly.
If you can tell me the size of your database and the number of stored procedures, I can help you plan a more precise timeline. SQL Server to Oracle Migration Guide • Blog – Ispirer