Oracle 23ai Compatibility Matrix

Comprehensive compatibility reference for HeliosDB’s Oracle 23ai implementation. This document provides detailed feature-by-feature compatibility information.

Table of Contents

• Overall Compatibility Summary
• SQL Language Support
• PL/SQL Support
• DBMS Packages
• Data Types
• Built-in Functions
• Advanced Features
• Known Limitations
• Behavioral Differences

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Overall Compatibility Summary

Compatibility Level

HeliosDB Full’s Oracle compatibility module covers a large part of Oracle’s SQL and PL/SQL feature surface, at the maturity levels shown below. Through the Oracle listener today, table definitions, INSERT/UPDATE/DELETE and common queries run unchanged, while Oracle-specific syntax, most built-in functions and PL/SQL need rewriting; see Oracle compatibility for in-house applications for results by usage area and how to assess your own application. It is not a drop-in replacement.

Module coverage, not listener behaviour

The tables on this page describe the Oracle compatibility module in the HeliosDB Full code base. What a client gets through the Oracle listener today was measured feature by feature: PL/SQL blocks report success without running, MERGE reports success without changing rows, CONNECT BY, PIVOT, INSERT ALL, RETURNING INTO, identity columns and synonyms are refused, and several Oracle functions (NVL, DECODE, INITCAP, LPAD, TRIM, REPLACE, SUBSTR, ROUND) return wrong results. Use Oracle compatibility for in-house applications and the Oracle Quick Start to plan, and test every statement your application sends.

Category	Maturity	Hardened
Core SQL	Supported	Yes
DDL Statements	Supported	Yes
DML Statements	Supported	Yes
PL/SQL Core	Beta	Limited
PL/SQL Packages	Beta	No
DBMS Packages	Partial	Limited
Hierarchical Queries	Supported	Yes
Analytic Functions	Supported	Yes
JSON Functions	Supported	Yes
XML Functions	Alpha	No
Object Types	Alpha	No
Collections	Beta	Limited
Triggers	Beta	Limited
Large Objects	Beta	Limited

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SQL Language Support

Data Definition Language (DDL)

Statement	Result	Notes
CREATE TABLE	Supported	Most options supported
CREATE TABLE AS SELECT	Supported	Basic CTAS
ALTER TABLE	Supported	Common alterations
DROP TABLE	Supported	CASCADE, PURGE
TRUNCATE TABLE	Supported	REUSE STORAGE partial
CREATE INDEX	Supported	B-tree, basic bitmap
CREATE UNIQUE INDEX	Supported
DROP INDEX	Supported
CREATE VIEW	Supported	WITH CHECK OPTION
CREATE OR REPLACE VIEW	Supported
DROP VIEW	Supported
CREATE MATERIALIZED VIEW	Partial	Basic refresh only
CREATE SEQUENCE	Supported	CACHE, NOCACHE
ALTER SEQUENCE	Supported	Basic modifications
DROP SEQUENCE	Supported
CREATE SYNONYM	Supported	PUBLIC, PRIVATE
DROP SYNONYM	Supported
CREATE TYPE	Partial	Simple object types
CREATE PROCEDURE	Supported	See PL/SQL section
CREATE FUNCTION	Supported	See PL/SQL section
CREATE PACKAGE	Partial	See PL/SQL section
CREATE TRIGGER	Partial	Row-level triggers
CREATE CLUSTER	Not Supported
CREATE CONTEXT	Not Supported
CREATE DATABASE LINK	Not Supported
CREATE DIRECTORY	Partial	Limited I/O
COMMENT ON	Supported
GRANT	Supported	Basic privileges
REVOKE	Supported	Basic privileges

Data Manipulation Language (DML)

Statement	Result	Notes
SELECT	Supported	See query features
INSERT	Supported	Single and multi-row
INSERT ALL	Partial	Conditional limited
INSERT FIRST	Partial
UPDATE	Supported
DELETE	Supported
MERGE	Supported	Basic merge operations
SELECT FOR UPDATE	Supported	NOWAIT, WAIT n
LOCK TABLE	Partial	Basic modes

Query Features

Feature	Result	Notes
Basic SELECT	Supported
WHERE clause	Supported
ORDER BY	Supported	NULLS FIRST/LAST
GROUP BY	Supported
GROUP BY ROLLUP	Supported
GROUP BY CUBE	Partial
GROUP BY GROUPING SETS	Partial
HAVING	Supported
DISTINCT	Supported
Table aliases	Supported
Column aliases	Supported
Subqueries	Supported	Correlated supported
Scalar subqueries	Supported
WITH clause (CTEs)	Supported
Recursive CTEs	Partial	Basic recursion
UNION	Supported
UNION ALL	Supported
INTERSECT	Supported
MINUS	Supported
INNER JOIN	Supported
LEFT/RIGHT OUTER JOIN	Supported
FULL OUTER JOIN	Supported
CROSS JOIN	Supported
NATURAL JOIN	Partial
USING clause	Supported
Oracle (+) syntax	Partial	Prefer ANSI joins
FETCH FIRST n ROWS	Supported	Oracle 12c+
OFFSET n ROWS	Supported
ROWNUM	Supported	See limitations

Hierarchical Query Features

Feature	Result	Notes
CONNECT BY	Supported
START WITH	Supported
PRIOR	Supported
LEVEL	Supported
CONNECT_BY_ROOT	Supported
SYS_CONNECT_BY_PATH	Supported
CONNECT_BY_ISLEAF	Supported
CONNECT_BY_ISCYCLE	Partial
NOCYCLE	Supported
ORDER SIBLINGS BY	Partial

Advanced Query Features

Feature	Result	Notes
PIVOT	Partial	Static pivot
UNPIVOT	Partial
MODEL clause	Not Supported	Planned
MATCH_RECOGNIZE	Not Supported
Flashback queries	Partial	AS OF timestamp
SAMPLE clause	Partial
XMLTABLE	Partial
JSON_TABLE	Supported
Lateral inline views	Partial
CROSS APPLY	Partial
OUTER APPLY	Partial

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PL/SQL Support

PL/SQL roadmap

PL/SQL execution through the Oracle listener — procedures, functions, anonymous blocks and common DBMS_ packages — is on the roadmap. Today, port PL/SQL to PL/pgSQL functions and run them through the PostgreSQL interface, or move the logic into the application tier. The tables in this section describe the PL/SQL coverage of the Oracle compatibility module, which is the planned scope for the Oracle listener.

Language Constructs

Construct	Result	Notes
Anonymous blocks	Supported	DECLARE/BEGIN/END
Variables	Supported	Most scalar types
Constants	Supported
%TYPE	Supported
%ROWTYPE	Supported
IF-THEN-ELSE	Supported
CASE statement	Supported	Simple and searched
Simple LOOP	Supported
WHILE LOOP	Supported
FOR LOOP	Supported	Numeric ranges
Cursor FOR LOOP	Supported
EXIT/EXIT WHEN	Supported
CONTINUE	Supported
GOTO	Partial	Limited support
NULL statement	Supported
RETURN	Supported
Nested blocks	Supported
Labels	Partial

Procedures and Functions

Feature	Result	Notes
CREATE PROCEDURE	Supported
CREATE FUNCTION	Supported
CREATE OR REPLACE	Supported
IN parameters	Supported
OUT parameters	Supported
IN OUT parameters	Partial
DEFAULT values	Supported
NOCOPY hint	Ignored	Syntax accepted
DETERMINISTIC	Partial	Hint only
RESULT_CACHE	Not Supported
AUTHID CURRENT_USER	Partial
AUTHID DEFINER	Partial
Named notation	Supported
Positional notation	Supported
Mixed notation	Partial

Packages

Feature	Result	Notes
Package specification	Partial
Package body	Partial
Package variables	Partial	Session state limited
Package constants	Partial
Package types	Partial
Package cursors	Partial
Package initialization	Partial
Overloading	Partial
PRAGMA SERIALLY_REUSABLE	Not Supported
Package state	Limited	Per-session state

Cursors

Feature	Result	Notes
Explicit cursors	Supported
OPEN	Supported
FETCH	Supported
CLOSE	Supported
%FOUND	Supported
%NOTFOUND	Supported
%ROWCOUNT	Supported
%ISOPEN	Supported
Cursor parameters	Partial
REF CURSOR	Partial	Weak cursors
SYS_REFCURSOR	Partial
Cursor variables	Partial
Cursor expressions	Partial
Implicit cursors	Supported	SQL%* attributes

Exception Handling

Feature	Result	Notes
EXCEPTION block	Supported
WHEN…THEN	Supported
WHEN OTHERS	Supported
NO_DATA_FOUND	Supported
TOO_MANY_ROWS	Supported
DUP_VAL_ON_INDEX	Supported
INVALID_CURSOR	Supported
CURSOR_ALREADY_OPEN	Supported
VALUE_ERROR	Supported
ZERO_DIVIDE	Supported
INVALID_NUMBER	Supported
LOGIN_DENIED	Partial
PROGRAM_ERROR	Partial
SQLCODE	Supported
SQLERRM	Supported
RAISE	Supported
RAISE_APPLICATION_ERROR	Supported
User-defined exceptions	Supported
EXCEPTION_INIT	Partial

Bulk Operations

Feature	Result	Notes
BULK COLLECT	Partial	Simple cases
BULK COLLECT LIMIT	Partial
FORALL	Partial
FORALL INDICES OF	Partial
FORALL VALUES OF	Partial
SAVE EXCEPTIONS	Partial
SQL%BULK_EXCEPTIONS	Partial
SQL%BULK_ROWCOUNT	Partial

Collections

Feature	Result	Notes
Nested tables	Partial
VARRAYs	Partial
Associative arrays	Partial
INDEX BY PLS_INTEGER	Supported
INDEX BY VARCHAR2	Partial
Collection methods	Partial	COUNT, FIRST, LAST
EXISTS	Partial
COUNT	Partial
FIRST/LAST	Partial
NEXT/PRIOR	Partial
EXTEND	Partial
TRIM	Partial
DELETE	Partial
Nested table operators	Not Supported

Triggers

Feature	Result	Notes
BEFORE INSERT	Supported
AFTER INSERT	Supported
BEFORE UPDATE	Supported
AFTER UPDATE	Supported
BEFORE DELETE	Supported
AFTER DELETE	Supported
FOR EACH ROW	Supported
Statement-level	Partial
:new/:old	Supported
WHEN clause	Partial
INSTEAD OF	Partial	Views only
COMPOUND triggers	Not Supported
System triggers	Not Supported
DDL triggers	Not Supported

Advanced PL/SQL

Feature	Result	Notes
Autonomous transactions	Not Supported	Planned
Pipelined functions	Not Supported
Parallel enable	Not Supported
PRAGMA RESTRICT_REFERENCES	Ignored
PRAGMA INLINE	Ignored
Native compilation	Not Supported
Conditional compilation	Partial
Object types in PL/SQL	Partial
Dynamic SQL (EXECUTE IMMEDIATE)	Partial
DBMS_SQL	Partial	See package section

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DBMS Packages

DBMS_OUTPUT

Function/Procedure	Result	Notes
PUT_LINE	Supported	Full
PUT	Supported	Full
NEW_LINE	Supported	Full
GET_LINE	Supported
GET_LINES	Partial
ENABLE	Supported
DISABLE	Supported

DBMS_LOB

Function/Procedure	Result	Notes
GETLENGTH	Supported
SUBSTR	Supported
INSTR	Supported
APPEND	Supported
COPY	Partial
ERASE	Partial
TRIM	Partial
WRITE	Partial
READ	Partial
COMPARE	Partial
CREATETEMPORARY	Partial
FREETEMPORARY	Partial
ISTEMPORARY	Partial
LOADFROMFILE	Not Supported
LOADBLOBFROMFILE	Not Supported
LOADCLOBFROMFILE	Not Supported
CONVERTTOBLOB	Partial
CONVERTTOCLOB	Partial

DBMS_SQL

Function/Procedure	Result	Notes
OPEN_CURSOR	Supported
PARSE	Supported
BIND_VARIABLE	Partial	Scalar types
BIND_ARRAY	Not Supported
DEFINE_COLUMN	Partial
EXECUTE	Supported
EXECUTE_AND_FETCH	Partial
FETCH_ROWS	Partial
COLUMN_VALUE	Partial
VARIABLE_VALUE	Partial
CLOSE_CURSOR	Supported
IS_OPEN	Supported
LAST_ROW_COUNT	Partial
LAST_ERROR_POSITION	Partial
DESCRIBE_COLUMNS	Not Supported
DESCRIBE_COLUMNS2	Not Supported
TO_REFCURSOR	Not Supported
TO_CURSOR_NUMBER	Not Supported

DBMS_UTILITY

Function/Procedure	Result	Notes
FORMAT_ERROR_BACKTRACE	Supported
FORMAT_ERROR_STACK	Supported
FORMAT_CALL_STACK	Partial
GET_TIME	Supported	Centiseconds
GET_CPU_TIME	Partial
COMMA_TO_TABLE	Supported
TABLE_TO_COMMA	Supported
NAME_RESOLVE	Partial
NAME_TOKENIZE	Partial
DB_VERSION	Partial
CURRENT_INSTANCE	Partial
EXEC_DDL_STATEMENT	Partial
COMPILE_SCHEMA	Not Supported
ANALYZE_SCHEMA	Not Supported

DBMS_METADATA

Function/Procedure	Result	Notes
GET_DDL	Partial	Tables, indexes
GET_DEPENDENT_DDL	Partial
SET_TRANSFORM_PARAM	Partial
OPEN	Partial
SET_FILTER	Partial
SET_COUNT	Partial
FETCH_DDL	Partial
CLOSE	Partial

DBMS_SCHEDULER

Function/Procedure	Result	Notes
CREATE_JOB	Partial	Basic jobs
DROP_JOB	Supported
ENABLE	Supported
DISABLE	Supported
RUN_JOB	Supported
STOP_JOB	Supported
CREATE_SCHEDULE	Partial
DROP_SCHEDULE	Partial
CREATE_PROGRAM	Partial
DROP_PROGRAM	Partial
CREATE_CHAIN	Not Supported
CREATE_WINDOW	Not Supported
SET_ATTRIBUTE	Partial

DBMS_STATS

Function/Procedure	Result	Notes
GATHER_TABLE_STATS	Partial	Basic statistics
GATHER_INDEX_STATS	Partial
GATHER_SCHEMA_STATS	Partial
GATHER_DATABASE_STATS	Not Supported
DELETE_TABLE_STATS	Partial
DELETE_INDEX_STATS	Partial
SET_TABLE_STATS	Partial
GET_TABLE_STATS	Partial
CREATE_STAT_TABLE	Not Supported
EXPORT_TABLE_STATS	Not Supported
IMPORT_TABLE_STATS	Not Supported

UTL_FILE

Function/Procedure	Result	Notes
FOPEN	Partial	Limited modes
FCLOSE	Supported
FCLOSE_ALL	Supported
GET_LINE	Supported
PUT	Supported
PUT_LINE	Supported
NEW_LINE	Supported
FFLUSH	Supported
FSEEK	Not Supported
FGETPOS	Not Supported
IS_OPEN	Partial
FCOPY	Not Supported
FGETATTR	Not Supported
FREMOVE	Partial
FRENAME	Partial

DBMS_RANDOM

Function/Procedure	Result	Notes
INITIALIZE	Supported
SEED	Partial
RANDOM	Partial
VALUE	Supported
VALUE (range)	Supported
STRING	Supported
NORMAL	Partial
TERMINATE	Supported

Other Packages

Package	Result	Notes
DBMS_SESSION	Partial	SET_IDENTIFIER only
DBMS_APPLICATION_INFO	Partial	SET_MODULE, SET_ACTION
DBMS_CRYPTO	Partial	Basic encryption
DBMS_LOCK	Not Supported
DBMS_PIPE	Not Supported
DBMS_ALERT	Not Supported
DBMS_AQ	Not Supported
DBMS_AQADM	Not Supported
DBMS_JOB	Deprecated	Use DBMS_SCHEDULER
DBMS_PARALLEL_EXECUTE	Not Supported
DBMS_FLASHBACK	Not Supported	Use MVCC
DBMS_REDEFINITION	Not Supported
DBMS_XA	Not Supported
UTL_HTTP	Not Supported
UTL_SMTP	Not Supported
UTL_TCP	Not Supported
UTL_RAW	Partial
UTL_ENCODE	Partial

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Data Types

Scalar Data Types

Type	Result	Notes
NUMBER	Supported	Full precision
NUMBER(p)	Supported
NUMBER(p,s)	Supported
INTEGER	Supported	Maps to NUMBER(38)
SMALLINT	Supported
DECIMAL	Supported
FLOAT	Supported
BINARY_FLOAT	Supported	IEEE 754
BINARY_DOUBLE	Supported	IEEE 754
VARCHAR2(n)	Supported	Up to 32767
NVARCHAR2(n)	Supported	Unicode
CHAR(n)	Supported	Fixed length
NCHAR(n)	Supported	Unicode
CLOB	Supported
NCLOB	Supported	Unicode
BLOB	Supported
BFILE	Partial	Read-only
RAW(n)	Supported
LONG	Supported	Deprecated
LONG RAW	Supported	Deprecated
DATE	Supported
TIMESTAMP	Supported
TIMESTAMP WITH TIME ZONE	Supported
TIMESTAMP WITH LOCAL TIME ZONE	Partial
INTERVAL YEAR TO MONTH	Supported
INTERVAL DAY TO SECOND	Supported
ROWID	Supported	Different format
UROWID	Partial
BOOLEAN (PL/SQL)	Supported
PLS_INTEGER	Supported
BINARY_INTEGER	Supported
SIMPLE_INTEGER	Partial
SIMPLE_FLOAT	Partial
SIMPLE_DOUBLE	Partial

Complex Types

Type	Result	Notes
Object types	Partial	Simple structures
Nested tables	Partial
VARRAYs	Partial
REF types	Not Supported
Opaque types	Not Supported

XML Types

Type	Result	Notes
XMLType	Partial	Basic operations
createXML	Partial
extract	Partial	XPath
extractValue	Partial
existsNode	Partial
XMLQuery	Partial
XMLTable	Partial
XMLELEMENT	Partial
XMLFOREST	Partial
XMLAGG	Partial

JSON Types

Type	Result	Notes
JSON	Supported	Native JSON type
JSON_VALUE	Supported
JSON_QUERY	Supported
JSON_TABLE	Supported
JSON_EXISTS	Supported
JSON_OBJECT	Supported
JSON_ARRAY	Supported
JSON_OBJECTAGG	Supported
JSON_ARRAYAGG	Supported
IS JSON	Supported
JSON_SERIALIZE	Partial
JSON_MERGEPATCH	Partial
JSON_TRANSFORM	Not Supported

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Built-in Functions

String Functions

Function	Result	Oracle Behavior Preserved
CONCAT	Supported	Yes
SUBSTR	Supported	Yes (negative position)
LENGTH	Supported	Yes
INSTR	Supported	Yes (nth occurrence)
UPPER	Supported	Yes
LOWER	Supported	Yes
INITCAP	Supported	Yes
LPAD	Supported	Yes
RPAD	Supported	Yes
LTRIM	Supported	Yes (trim set)
RTRIM	Supported	Yes (trim set)
TRIM	Supported	Yes
REPLACE	Supported	Yes
TRANSLATE	Supported	Yes
REVERSE	Supported	Yes
ASCII	Supported	Yes
CHR	Supported	Yes
SOUNDEX	Partial	Approximate
REGEXP_LIKE	Supported	Most patterns
REGEXP_REPLACE	Supported	Most patterns
REGEXP_SUBSTR	Supported	Most patterns
REGEXP_INSTR	Partial	Basic patterns
REGEXP_COUNT	Partial	Basic patterns
NVL	Supported	Yes
NVL2	Supported	Yes
DECODE	Supported	Yes
COALESCE	Supported	Yes
NULLIF	Supported	Yes
LNNVL	Partial
NANVL	Partial

Numeric Functions

Function	Result	Notes
ABS	Supported
CEIL	Supported
FLOOR	Supported
ROUND	Supported
TRUNC	Supported
MOD	Supported
POWER	Supported
SQRT	Supported
EXP	Supported
LN	Supported
LOG	Supported
SIGN	Supported
SIN, COS, TAN	Supported
ASIN, ACOS, ATAN	Supported
SINH, COSH, TANH	Supported
GREATEST	Supported	NULL propagation
LEAST	Supported	NULL propagation
WIDTH_BUCKET	Partial
REMAINDER	Supported
BITAND	Supported

Date/Time Functions

Function	Result	Notes
SYSDATE	Supported
SYSTIMESTAMP	Supported
CURRENT_DATE	Supported	Session TZ
CURRENT_TIMESTAMP	Supported	Session TZ
LOCALTIMESTAMP	Supported
DBTIMEZONE	Partial
SESSIONTIMEZONE	Supported
ADD_MONTHS	Supported	Month-end handling
MONTHS_BETWEEN	Supported	Fractional
LAST_DAY	Supported
NEXT_DAY	Supported
ROUND (date)	Supported	Format models
TRUNC (date)	Supported	Format models
EXTRACT	Supported
TO_DATE	Supported	Format models
TO_CHAR	Supported	Format models
TO_TIMESTAMP	Supported
TO_TIMESTAMP_TZ	Partial
TO_DSINTERVAL	Partial
TO_YMINTERVAL	Partial
FROM_TZ	Partial
NEW_TIME	Partial
TZ_OFFSET	Partial

Aggregate Functions

Function	Result	Notes
COUNT	Supported	Including DISTINCT
SUM	Supported
AVG	Supported
MIN	Supported
MAX	Supported
LISTAGG	Supported
MEDIAN	Partial
PERCENTILE_CONT	Partial
PERCENTILE_DISC	Partial
STDDEV	Supported
STDDEV_POP	Supported
STDDEV_SAMP	Supported
VARIANCE	Supported
VAR_POP	Supported
VAR_SAMP	Supported
COVAR_POP	Partial
COVAR_SAMP	Partial
CORR	Partial
REGR_*	Partial	Basic regression
STATS_*	Not Supported
COLLECT	Partial
XMLAGG	Partial

Analytic Functions

Function	Result	Notes
ROW_NUMBER	Supported
RANK	Supported
DENSE_RANK	Supported
NTILE	Supported
LAG	Supported
LEAD	Supported
FIRST_VALUE	Supported
LAST_VALUE	Supported
NTH_VALUE	Partial
CUME_DIST	Partial
PERCENT_RANK	Partial
RATIO_TO_REPORT	Partial
FIRST/LAST	Partial
KEEP	Partial	FIRST/LAST only
OVER clause	Supported
PARTITION BY	Supported
ORDER BY	Supported
ROWS/RANGE	Supported
UNBOUNDED	Supported
CURRENT ROW	Supported

Conversion Functions

Function	Result	Notes
TO_CHAR	Supported	Most formats
TO_NUMBER	Supported
TO_DATE	Supported	Most formats
TO_TIMESTAMP	Supported
TO_CLOB	Partial
TO_BLOB	Partial
TO_LOB	Partial
CAST	Supported	Most conversions
CONVERT	Partial	Character sets
HEXTORAW	Supported
RAWTOHEX	Supported
ROWIDTOCHAR	Partial
CHARTOROWID	Partial

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Advanced Features

Flashback Support

Feature	Result	Notes
AS OF TIMESTAMP	Partial	Uses MVCC
AS OF SCN	Not Supported
VERSIONS BETWEEN	Not Supported
Flashback Table	Not Supported
Flashback Drop	Not Supported
Flashback Database	Not Supported

Partitioning

Feature	Result	Notes
Range partitioning	Partial	Basic
List partitioning	Partial	Basic
Hash partitioning	Partial	Basic
Composite partitioning	Not Supported
Interval partitioning	Not Supported
Reference partitioning	Not Supported
Partition pruning	Partial

Advanced Security

Feature	Result	Notes
Virtual Private Database	Not Supported
Label Security	Not Supported
Transparent Data Encryption	Not Supported	Use HeliosDB encryption
Data Masking	Not Supported
Database Vault	Not Supported
Audit Vault	Not Supported

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Known Limitations

Not Supported Features

Feature	Alternative
Oracle RAC	HeliosDB native clustering
Data Guard	HeliosDB replication
ASM	Standard filesystem storage
Streams/GoldenGate	HeliosDB CDC (connectors planned)
Oracle Spatial (SDO_*)	Not available
Oracle Text	HeliosDB full-text search
Java stored procedures	Use PL/pgSQL or external
APEX	Web UI alternatives
Oracle Forms	Web UI alternatives

SQL Limitations

1. ROWNUM: Works in simple cases but complex ROWNUM usage may behave differently
2. MODEL clause: Not supported; use application logic
3. MATCH_RECOGNIZE: Pattern matching not available
4. CONNECT BY: Limited to 1000 levels by default
5. Recursive CTEs: Basic recursion only

PL/SQL Limitations

These apply to the planned PL/SQL support (see PL/SQL Support):

1. Autonomous transactions: Not supported
2. Pipelined functions: Not supported
3. Package state: Limited session state management
4. Native compilation: Interpreted only
5. Complex object types: Basic structures only

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Behavioral Differences

NULL Handling

• Oracle empty strings are treated as NULL; HeliosDB distinguishes empty strings from NULL
• Use NVL() or COALESCE() for consistent behavior

ROWID Format

• HeliosDB uses a different internal ROWID format
• ROWID values are not portable between systems

Sequence Behavior

• Caching behavior may differ slightly
• CURRVAL requires NEXTVAL to be called first in the same session

Transaction Isolation

• Uses HeliosDB’s MVCC implementation
• Snapshot isolation is the default

Date Arithmetic

• Oracle allows direct date + number operations
• Some edge cases with month-end dates may differ

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Related Documentation

• README.md - Protocol overview
• CONFIGURATION.md - Server configuration
• EXAMPLES.md - Working examples
• PLSQL_SUPPORT.md - PL/SQL details

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Compatibility target: Oracle 23ai