- What's New
- Service Overview
- Getting Started
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User Guide
- Database Evaluation
- Object Migration
- SQL Statement Conversion
- Conversion Configuration
- SQL Audit
- Data Source Management
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- Interconnection with CTS
- Best Practices
- Security White Paper
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API Reference
- Before You Start
- API Types
- Calling APIs
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API
- API Version Management
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- SQL Statement Conversion
- Evaluation Project
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Migration Project
- Creating a Migration Project
- Querying Migration Projects
- Querying the Status of a Migration Project
- Checking Target Database Permissions
- Querying Permission Check Results
- Querying Migration Project Details
- Submitting Syntax Conversion of Objects
- Querying Syntax Conversion Progress of Objects
- Submitting Verification
- Querying the Verification Progress
- Downloading a Migration Error Report
- Deleting a Migration Project
- Permissions Policies and Supported Actions
- Appendixes
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FAQs
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Product Consulting
- Instance Freezing, Release, and Deletion
- Which Schemas in Source Databases Are Ignored for Migration?
- What Are the Differences Between Syntax Conversion and Migration & Verification in a Migration Project?
- What Are the Database Schema Changes After an Oracle Database Is Migrated to the Target Database?
- Why Cannot I Use Some Functions?
- What Is the Function of the dsc_ora_ext Schema Generated After Migration to the Target Database?
- What Should I Do If Data Collection Fails or Is Slow Due to the Small Values of Certain Oracle SGA Parameters?
- What Should I Do If Data Collection Fails and a Message SNAPSHOT TOO OLD Is Displayed?
- What Is the Mapping Between the GaussDB Versions Displayed on the UGO Console and Self-built GaussDB Versions?
- What Are VPCEP Resource Quotas?
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Database Connections
- What Should I Do If I Cannot Connect to the Source Oracle Database During Database Evaluation Project Creation?
- What Should I Do If I Failed To Connect to the Source Database as User sys?
- How Do I Create GaussDB Databases Compatible with Source Databases?
- What Should I Do If My Database Fails to be Connected?
- SQL Server Connection Test Failed (Error Code=0, SQLState=08S01)
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Evaluation Project
- How Do I Select a Connection Method?
- How Does UGO Collect Data from Source Databases?
- How Does UGO Check Database Permissions?
- What Are the Possible Causes for an Object Collection Failure?
- In GaussDB, How Do I Configure a Search Path If A Statement Without Schema Name Fails To Be Executed?
- What Is Native Compatibility, Conversion Compatibility, Partial Compatibility, or Incompatibility?
- What Is the Relationship Between Migration Risk (Top 10 risk SQL) and Risky SQL Summary?
- What Are Reconstruction Statistics and How Are Reconstruction Points Measured?
- What Should I Do If An Object Collection Error (Closed Connection) Is Displayed During Evaluation Project Creation?
- What Should I Do If "ErrorCode=4036" Is Displayed During Evaluation Project Creation?
- What Should I Do If "ErrorCode=17002" Is Displayed During Evaluation Project Creation?
- What Do I Do If the Assessment Task Is Connected but the Pre-check Fails?
- What Is the Impact of the Collection on the Source Database?
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Migration Project
- Why Is There No Available Evaluation Project During Migration Project Creation?
- When Should I Use the Conversion Config Function?
- What Should I Do If SQL Modifications Failed to Be Saved During Object Correction?
- How Do I Solve ERROR: syntax error at or near "@"?
- What Are the Possible Causes for an Object Verification Failure?
- What Are the Impacts of GUC Parameter Settings of GaussDB on Migration?
- How Do I Set GaussDB GUC Parameters?
- Why Is the Number of Indexes Different After Oracle Data is Migrated to GaussDB?
- What Should I Do If There Are ctid, xc_node_id, and tableoid Columns in GaussDB?
- Why Is Data Inconsistent When SELECT Statements Without ORDER BY Are Used for Query in Distributed GaussDB?
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Product Consulting
- Videos
- General Reference
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Converting Syntax
Converting DATE and TIME Functions
When you convert syntax to GaussDB V2.0-3.2 and earlier versions, the DATE and TIME functions listed in Table 1 return the transaction start time. The time you obtained in the source database is the current system time. In long transactions, the time obtained from the source database is different from that obtained from the target GaussDB database. If the converted statement contains these functions, you need to analyze whether there are long transactions and confirm the impact. If yes, manually modify the functions to ensure final accuracy.
Oracle -> GaussDB
GaussDB supports only common synonyms and does not support public synonyms. UGO will convert public synonyms in an Oracle database to common synonyms of the public schema in a GaussDB database. For details, see Table 2.
If different users in your database have public synonyms with the same name, there are synonym conflicts. You need to reconstruct the synonyms with the same name before migrating them. For details, see Table 3.
Converting Syntax from PostgreSQL to GaussDB
Mode compatibility:
- Syntax can be migrated from PostgreSQL to GaussDB (O-compatible mode).
- In the GaussDB (O-compatible mode) database, an empty string is stored as null. If True is returned in the result after select '' is null; is executed, an empty string is also stored as null in the Oracle database.
Impact scope:
- If the source database type is PostgreSQL and the target database type is GaussDB (O-compatible mode), SQL statements containing empty character strings or null need to be reconstructed.
- The impact scope includes DML, DDL, and system functions, such as select'' is null; and select regexp_matches('test1', 'test1', '');.
- UGO can evaluate the IS NULL syntax and empty string syntax during migration from PostgreSQL to GaussDB.
Converting Syntax from Microsoft SQL Server to MySQL
The DATETIME data type of Microsoft SQL Server supports addition and subtraction operations. However, UGO cannot accurately identify this scenario, so the DATE_ADD function is recommended in the MySQL database for reconstruction.
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