Planning Data Export

For details about the data types that can be exported to MRS, see Table 2.

**Table 1** Mapping between ORC write-only foreign tables and Hive data types
Type	Type Supported by GaussDB(DWS) Internal Tables (Data Source Table)	Type Supported by GaussDB(DWS) Write-only Foreign Tables	Hive Table Type
1-byte integer	TINYINT	TINYINT (not recommended)	SMALLINT
1-byte integer	TINYINT	SMALLINT (recommended)	SMALLINT
2-byte integer	SMALLINT	SMALLINT	SMALLINT
4-byte integer	INTEGER, BINARY_INTEGER	INTEGER	INT
8-byte integer	BIGINT	BIGINT	BIGINT
Single-precision floating point number	FLOAT4, REAL	FLOAT4, REAL	FLOAT
Double-precision floating point number	DOUBLE PRECISION, FLOAT8, BINARY_DOUBLE	DOUBLE PRECISION, FLOAT8, BINARY_DOUBLE	DOUBLE
Scientific data type	DECIMAL, NUMERIC	DECIMAL[p (,s)] (The maximum precision can reach up to 38.)	precision ≤ 38: DECIMAL; precision > 38: STRING
Date type	DATE	TIMESTAMP[(p)] [WITHOUT TIME ZONE]	TIMESTAMP
Time type	TIME [(p)] [WITHOUT TIME ZONE], TIME [(p)] [WITH TIME ZONE]	TEXT	STRING
	TIMESTAMP[(p)] [WITHOUT TIME ZONE], TIMESTAMP[(p)][WITH TIME ZONE], SMALLDATETIME	TIMESTAMP[(p)] [WITHOUT TIME ZONE]	TIMESTAMP
	INTERVAL DAY (l) TO SECOND (p), INTERVAL [FIELDS] [(p)]	VARCHAR(n)	VARCHAR(n)
Boolean type	BOOLEAN	BOOLEAN	BOOLEAN
CHAR type	CHAR(n), CHARACTER(n), NCHAR(n)	CHAR(n), CHARACTER(n), NCHAR(n)	When n is less than or equal to 255, CHAR(n); when n is greater than 255, STRING
VARCHAR type	VARCHAR(n), CHARACTER VARYING(n), VARCHAR2(n)	VARCHAR(n)	n ≤ 65535: VARCHAR(n); n > 65535: STRING
VARCHAR type	NVARCHAR2(n)	TEXT	STRING
String (large text object)	TEXT, CLOB	TEXT, CLOB	STRING
Monetary type	MONEY	NUMERIC	BIGINT