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SQL Server to Oracle data types

Every SQL Server data type that Oracle stores differently, what the converter writes for it, when, and the report line.

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Each row is a type from SQL Server that Oracle stores differently: what the Oracle script gets, why, and the line the report writes about it. The rows come from the converter's own rules, so this page matches what it does.

Convert in the browser: SQL Server to Oracle opens the converter set up for this pair. The SQL Server to Oracle migration guide covers dumping, loading and the rules for keys, indexes and names.

A report line is a fix when the converter changed something and lists it, or a problem when a value or object is worth a look.

Numbers

In SQL Server In Oracle Why Report line
decimal(p,s), money, smallmoney NUMBER(p,s); money as NUMBER(19,4) NUMBER holds 38 digits, as decimal does, so every value is exact. None

Booleans and bits

In SQL Server In Oracle Why Report line
bit NUMBER(1) with a CHECK of 0 and 1 Oracle 21c has no boolean column type; 1 and 0 keep the values on every version. None

Text

In SQL Server In Oracle Why Report line
char(n), varchar(n), nchar(n), nvarchar(n) VARCHAR2(n CHAR), counting characters Lengths count characters as SQL Server's nvarchar does. None
varchar(max), nvarchar(max), text, ntext VARCHAR2(4000 CHAR) when every value fits 4000 bytes, else CLOB A VARCHAR2 holds 4000 bytes by default and Oracle can't index a CLOB, so text keeps VARCHAR2 when its values fit and is a CLOB when they don't. text_as_lob (fix)
empty strings and empty binary values NULL Oracle stores an empty string as NULL, so a value that was ' reads back as NULL. The report counts them per column. empty_string_null (problem)
NUL characters in text kept VARCHAR2 and CLOB can hold a NUL character, so the value is copied as it is. None
text that isn't valid in its encoding the bad bytes as the replacement character The script is UTF-8 and every value has to be valid text. invalid_utf8_replaced (problem)

Dates and times

In SQL Server In Oracle Why Report line
datetime, datetime2, smalldatetime TIMESTAMP(p) A datetime is a wall-clock reading, like Oracle's TIMESTAMP, which keeps up to nine digits of a second. date becomes DATE, which also holds a time of day that stays at midnight. None
datetimeoffset TIMESTAMP WITH TIME ZONE, with each value's offset Oracle keeps the offsets from -12:00 to +14:00; a value with an offset beyond -12:00 is written in UTC, the same instant. None
time INTERVAL DAY TO SECOND from midnight Oracle has no time-of-day type; an interval from midnight holds every value. None
dates that aren't valid NULL A value that isn't a date becomes NULL and the report counts it. date_out_of_range (problem)

Binary

In SQL Server In Oracle Why Report line
binary, varbinary, image RAW(n) and BLOB Bytes stay bytes. None
rowversion, timestamp BLOB, empty SQL Server sets a row version by itself and SSMS scripts no values for it. rowversion_empty (fix)

JSON, spatial and other types

In SQL Server In Oracle Why Report line
json (SQL Server 2025) CLOB The same JSON values, which Oracle's JSON functions read. None
uniqueidentifier VARCHAR2(36) The same identifiers, written in lowercase. None
geometry, geography BLOB with SQL Server's own bytes SSMS writes spatial values in SQL Server's serialization, which is kept byte for byte. spatial_as_native (fix)
xml, sql_variant, hierarchyid, vector VARCHAR2 or CLOB with each value's text Oracle has no equivalent type; xml and sql_variant keep each value's text and hierarchyid its path, such as /1/2/. type_replaced (fix)
types IntoSQL doesn't know CLOB Text holds any value; change the type after loading. unknown_type (problem)

Counters and identities

In SQL Server In Oracle Why Report line
IDENTITY GENERATED BY DEFAULT ON NULL AS IDENTITY, continuing after the highest id The copied ids load as they are, and the counter continues after the highest one. None

Other pairs