Oracle to MariaDB Migration

SQLines provides tools to help you transfer data, convert database schema (DDL), views, stored procedures, functions, packages, triggers, queries and SQL scripts from Oracle to MariaDB.

  • SQLines Data - Data transfer, schema migration and validation tool
  • SQLines SQL Converter - SQL scripts assessment and conversion tool

Databases:

  • Oracle 19c, 18c, 12c, 11g, 10g and 9i
  • MariaDB 10.x and 5.x

Starting from MariaDB 10.3 there is the Oracle compatibility mode, see Oracle to MariaDB Migration - Compatibility Mode.

Migration Reference

Identifiers

Max length:

Oracle MariaDB
Tables, columns, indexes, views, procedures, triggers 128 (was 30 before Oracle 12c) 64

SQL Language Elements

Converting SQL language elements:

Oracle MariaDB
1 -- comment Single line comment -- comment A blank is required after --

Oracle DATE arithmetic:

Oracle MariaDB
1 SYSDATE + 1 Add 1 day DATE_ADD(SYSDATE(), INTERVAL 1 DAY)
2 SYSDATE + 1/24 Add 1 hour DATE_ADD(SYSDATE(), INTERVAL 1 HOUR)
3 SYSDATE + 1/1440 Add 1 minute DATE_ADD(SYSDATE(), INTERVAL 1 MINUTE)
4 SYSDATE + 1/86400 Add 1 second DATE_ADD(SYSDATE(), INTERVAL 1 SECOND)

Operators and predicates:

Oracle MariaDB
1 (start1, end1) OVERLAPS (start2, end2) Check if two datetime
intervals overlap
(start2 < end1 AND end2 > start1)

Data Types

Character data types:

Oracle MariaDB
1 CLOB Character large object, <= 4G LONGTEXT
2 LONG Character data, <= 2G LONGTEXT

Unicode character data types:

Oracle MariaDB
1 NCHAR(n) Fixed-length Unicode string, n <= 2000 NCHAR(n) n <= 255
NVARCHAR(n) n > 255
2 NVARCHAR2(n) Variable-length Unicode string, n <= 4000 NVARCHAR(n) n <= 65,535
3 NCLOB Unicode large character object LONGTEXT

Numeric data types:

Oracle MariaDB
1 DECIMAL(p,s), DEC(p,s) Fixed-point number DECIMAL(p,s), DEC(p,s)

Date and time data types:

Oracle MariaDB
1 DATE Date and time with seconds DATETIME

Binary data types:

1 BLOB Binary large object, ⇐ 4G LONGBLOB
2 RAW(n) Variable-length binary data, 1 ⇐ n ⇐ 2000 VARBINARY(n)
3 LONG RAW Binary data, < 2G LONGBLOB

Other data types:

1 ROWID Physical row address CHAR(10)
2 XMLTYPE XML data LONGTEXT

Built-in SQL Functions

Converting string functions:

Oracle MariaDB
1 CHR(num) Get character from ASCII code CHR(num) since 10.3.1
2 INSTR(str, substr) Get position of substring INSTR(str, substr)
INSTR(str, substr, pos) LOCATE(substr, str, pos) param order
INSTR(str, substr, pos, num) User-defined function
3 LENGTH(string) Get length of string in chars CHAR_LENGTH(string)
4 LPAD(string, len, pad) Pad the left-side of string LPAD(string, len, pad)
5 LTRIM(string) Remove leading spaces LTRIM(string)
LTRIM(string, set) Remove leading chars TRIM(LEADING set FROM string)
6 MONTHS_BETWEEN(dt1, dt2) Get difference in months User-defined function
7 REPLACE(str, search) Remove search-string REPLACE(str, search, ")
REPLACE(str, search, replace) Replace search-string REPLACE(str, search, replace)
8 RPAD(string, len, pad) Pad the right-side of string RPAD(string, len, pad)
9 RTRIM(string) Remove trailing spaces RTRIM(string)
RTRIM(string, set) Remove trailing chars TRIM(TRAILING set FROM string)
10 SUBSTR(string, pos, len) Get a substring of string SUBSTR(string, pos, len)
11 TRANSLATE(string, from, to) Replace characters Nested REPLACE or User-defined function

Converting date and time functions:

Oracle MariaDB
1 ADD_MONTHS(date, num) Add num months to date TIMESTAMPADD(MONTH, num, date)
2 LAST_DAY(datetime) Get last day of the month,
includes time
LAST_DAY(datetime) Returns date only
3 TO_DATE(string, format) Convert string to datetime STR_TO_DATE(string, format)
TO_DATE(string) CAST(string AS DATETIME)

Converting NULL processing functions:

Oracle MariaDB
1 NVL(exp, replacement) Replace NULL with the specified value NVL(exp, replacement)

Converting math functions:

Oracle MariaDB
1 POWER(value, n) Raise value to the nth power POWER(value, n)

SELECT Statement

Converting SQL SELECT statement and its clauses:

Oracle MariaDB
1 select INTERSECT select2 Returns rows that exist in both queries select INTERSECT select2 Since 10.3.0

Sequences

Note that sequences are available since MariaDB 10.3

CREATE SEQUENCE and ALTER SEQUENCE statements:

Oracle MariaDB
1 CREATE SEQUENCE seqname CREATE [OR REPLACE] SEQUENCE seqname
2 ALTER SEQUENCE seqname ALTER SEQUENCE [IF EXISTS] seqname
3 INCREMENT BY num Positive or negative increment, default is 1 INCREMENT BY num
4 START WITH num Initial value START WITH num
5 MAXVALUE num Maximum value is num MAXVALUE num
NOMAXVALUE System limit NOMAXVALUE
6 MINVALUE num Minimum value is num MINVALUE num
NOMINVALUE System limit NOMINVALUE
7 CYCLE Reuse values after reaching the limit CYCLE
NOCYCLE No reuse, this is default NOCYCLE
8 CACHE num Cache num values, default is 20 CACHE num Default is 1000
NOCACHE Values are not preallocated NOCACHE
9 ORDER Guarantee numbers in order of requests Option not supported, commented
NOORDER No guarantee, this is default Option not supported, removed as it is default
10 NOKEEP Do not keep value during replay Option not supported, removed as it is default
11 NOSCALE Disable sequence scalability Option not supported, removed as it is default
12 GLOBAL A regular sequence visible to all sessions Option not supported, removed as it is default

Referencing sequence values:

Oracle MariaDB
1 seqname.CURRVAL The current value of seqname NEXTVAL(seqname) NEXT VALUE FOR seqname
2 seqname.NEXTVAL The next value of seqname LASTVAL(seqname) PREVIOUS VALUE FOR seqname

Note that in Oracle mode (sql_mode = oracle), you can use the Oracle syntax seqname.CURRVAL and seqname.NEXTVAL to get sequence values in MariaDB.

DROP SEQUENCE statement:

Oracle MariaDB
1 DROP SEQUENCE seqname DROP SEQUENCE [IF EXISTS] seqname

CREATE INDEX Statement

Converting CREATE INDEX statement keywords and clauses:

Oracle MariaDB
1 CREATE INDEX schema.index_name CREATE INDEX index_name Can contain index name only

SELECT Statement

Converting SQL SELECT statement and its clauses:

Oracle MariaDB
1 t1 JOIN t2 USING (column_name) USING clause for joins t1 JOIN t2 USING (column_name)
2 CONNECT BY PRIOR Hierarchical queries Recursive Common Table Expressions (CTE)

Rownum pseudo-column conditions:

Oracle MariaDB - Before 10.6.1 MariaDB - Since 10.6.1
1 ROWNUM = 1 Return 1 row only LIMIT 1 ROWNUM() = 1
ROWNUM <= n Row limit LIMIT n ROWNUM() <= n
ROWNUM < n LIMIT n - 1 ROWNUM() < n