MySQL
MySQL#
When the data type of a table column is VARCHAR or CHAR with a size of 1 or 2, data of size 1 is migrated to null.#
Cause#
If you find that the MySQL JDBC driver returns a null value when importing data with a size of 1, it is probably a MySQL JDBC driver issue.
Solution#
You need to replace the driver with version 5.0.8 of MySQL Connector/J. If the same happens in the retry, cancel Batch Execution by following the procedure below.
- Open the project.
- Click the menu "Migration" → "Migration Options".
- Change the value of "Batch Execution" to "No".
Data types CHAR and VARCHAR are changed to NCHAR and NVARCHAR.#
Cause#
MySQL does not support NCHAR or NVARCHAR data types. Instead, it allows for user to specify national character set as an attribute of the CHAR or VARCHAR data type column. The Migration Center converts national character set specified CHAR or VARCHAR column to NCHAR and NVARCHAR column in order to migrate data successfully.
Solution#
This phenomenon is normal.
In the default DataType Map of Migration Center, MySQL's NVARCHAR is mapped to NVARCHAR (10666) in Altibase. If the number of bytes per character in the national character set between MySQL and Altibase is different, performing the escalation without consideration of this may cause the schema not to be generated beyond the limit byte count. To avoid this situation, the Migration Center basically fixed the size of the NVARCHAR.
If the data size of the corresponding table column is not large, you can transfer the size of the source database as it is by following the procedure below.
- Reconcile step: Click on "NVARCHAR" row in "Data Type Mapping"
- Click the "Change" button
- Select 'NVARCHAR' as Destination DB Data Type, leave Precision blank, and save