Heterogeneous databases support different data types. DTS maps a data type in the source database to a data type supported by the destination database during schema migration. This topic lists the data type mappings for you to evaluate the impact of data migration on your business.

For more information about data migration scenarios, see Overview of data migration scenarios.

TiDB-to-MySQL

Source: a user-created TiDB database

Target: a user-created MySQL database, an ApsaraDB RDS for MySQL database, or an ApsaraDB for PolarDB database

Data type in the TiDB database Data type in the MySQL database
BIGINT BIGINT
BINARY BINARY
BIT BIT
BOOL\ BOOLEAN TINYINT
CHAR CHAR
DATE DATE
DATETIME DATETIME
DECIMAL DECIMAL
DOUBLE DOUBLE
ENUM ENUM
FLOAT FLOAT
INT INT
INTEGER INTEGER
JSON JSON

MEDIUMBLOB/LONGBLOB

TINYBLOB/BLOB/

MEDIUMBLOB/LONGBLOB

TINYBLOB/BLOB/
MEDIUMINT MEDIUMINT
SET SET
SMALLINT SMALLINT
TEXT/LONGTEXT TEXT/LONGTEXT
TIME TIME
TIMESTAMP TIMESTAMP
TINYINT TINYINT
VARBINARY VARBINARY
VARCHAR VARCHAR
YEAR YEAR

Oracle-to-MySQL

Source: a user-created Oracle database

Target: a user-created MySQL database, an ApsaraDB RDS for MySQL database, or an ApsaraDB for PolarDB database

Data type in the Oracle database Data type in the MySQL database Supported by DTS
varchar2(n [char/byte]) varchar(n) Yes
nvarchar2[(n)] national varchar[(n)] Yes
char[(n [byte/char])] char[(n)] Yes
nchar[(n)] national char[(n)] Yes
number[(p[,s])] decimal[(p[,s])] Yes
float(p)] double Yes
long longtext Yes
date datetime Yes
binary_float decimal(65,8) Yes
binary_double double Yes
timestamp[(fractional_seconds_precision)] datetime[(fractional_seconds_precision)] Yes
timestamp[(fractional_seconds_precision)]with localtimezone datetime[(fractional_seconds_precision)] Yes
timestamp[(fractional_seconds_precision)]with localtimezone datetime[(fractional_seconds_precision)] Yes
clob longtext Yes
nclob longtext Yes
blob longblob Yes
raw varbinary(2000) Yes
long raw longblob Yes
bfile N/A No
interval year(year_precision) to month N/A No
interval day(day_precision)to second[(fractional_seconds_precision)] N/A No
Note
  • A char column with a length greater than 255 bytes is converted to the varchar(n) type.
  • Data types such as bfile, interval year to month, and interval day to second in Oracle databases are not supported in MySQL databases. They cannot be converted to data types supported by the destination database during schema migration.

    The schema migration fails if the table to be migrated contains these three data types. You must make sure that columns with these three data types are excluded from the objects to be migrated.

  • The timestamp data type of MySQL databases does not contain the time zone information. However, the timestamp with time zone and timestamp with local time zone data types in Oracle databases provide time zone information. Therefore, DTS converts the values of these data types based on the time zone to UTC time for storage in the destination instance.

Migrate data from a user-created Oracle database to a database under a DRDS instance

Data type in the Oracle database Data type in the DRDS database Supported by DTS
varchar2(n [char/byte]) varchar(n) Yes
nvarchar2[(n)] national varchar[(n)] Yes
char[(n [byte/char])] char[(n)] Yes
nchar[(n)] national char[(n)] Yes
number[(p[,s])] decimal[(p[,s])] Yes
float(p)] double Yes
long longtext Yes
date datetime Yes
binary_float decimal(65,8) Yes
binary_double double Yes
timestamp[(fractional_seconds_precision)] datetime[(fractional_seconds_precision)] Yes
timestamp[(fractional_seconds_precision)]with localtimezone datetime[(fractional_seconds_precision)] Yes
timestamp[(fractional_seconds_precision)]with localtimezone datetime[(fractional_seconds_precision)] Yes
clob longtext Yes
nclob longtext Yes
blob longblob Yes
raw varbinary(2000) Yes
long raw longblob Yes
bfile N/A No
interval year(year_precision) to month N/A No
interval day(day_precision)to second[(fractional_seconds_precision)] N/A No
Note
  • A char column with a length greater than 255 bytes is converted to the varchar(n) type in the DRDS database.
  • The timestamp data type of DRDS databases does not contain the time zone information. However, the timestamp with time zone and timestamp with local time zone data types in Oracle databases provide time zone information. Therefore, DTS converts the values of these data types based on the time zone to UTC time for storage in the destination instance.

Migrate data from a user-created Oracle database to an ApsaraDB RDS for PPAS database

Data type in the Oracle database Data type in the ApsaraDB RDS for PPAS database Supported by DTS
varchar2(n [char/byte]) varchar2[(n)] Yes
nvarchar2[(n)] nvarchar2[(n)] Yes
char[(n [byte/char])] char[(n)] Yes
nchar[(n)] nchar[(n)] Yes
number[(p[,s])] number[(p[,s])] Yes
float(p)] double precision Yes
long long Yes
date date Yes
binary_float real Yes
binary_double double precision Yes
timestamp[(fractional_seconds_precision)] timestamp[(fractional_seconds_precision)] Yes
timestamp[(fractional_seconds_precision)]with time zone timestamp[(fractional_seconds_precision)]with time zone Yes
timestamp[(fractional_seconds_precision)]with local time zone timestamp[(fractional_seconds_precision)]with time zone Yes
clob clob Yes
nclob nclob Yes
blob blob Yes
raw raw(size) Yes
long raw long raw Yes
bfile N/A No
interval year(year_precision) to month interval year to month No
interval day(day_precision) to second[(fractional_seconds_precision)] interval day to second[(fractional_seconds_precision)] No
Note The timestamp[(fractional_seconds_precision)]with local time zone data type in Oracle databases is not supported in ApsaraDB RDS for PPAS databases. DTS converts the values of these data types based on the time zone to UTC time before storing them in the timestamp[(fractional_seconds_precision)]with time zone data type in the destination instance.