Known Issues

#1: Semantika will fail when using MySQL 5.1.x version because the server will assign data produced by CONCAT function as BLOB instead of VARCHAR datatype. It is recommended to use (or upgrade) to the latest 5.6.x version.

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#2: Semantika will fail to recognize the semantic of SQL join expression if SIMPLE JOIN is used in logical table query. Instead we encourage to use proper JOIN..ON expression to write table joining.

Avoid:

SELECT pid, label, price
FROM product, offer
WHERE product.pid = offer.pid

Recommended:

SELECT pid, label, price
FROM product
JOIN offer ON product.pid = offer.pid

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#3: Semantika will fail to parse SELF-JOIN expression in logical table query.

Avoid:

SELECT p1.own_name, p2.friend_name
FROM person p1
JOIN person p2 ON p1.pid = p2.fid

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#4: Semantika can fail when table alias is used in logical table query.

Avoid:

SELECT t1.name, t2.birthdate
FROM person t1

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#5: At the moment, Semantika supports open-source databases only, i.e., MySQL (5.3+), PostgreSQL (9.1+) and H2 (1.2+). Other database systems will be supported in the future.

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#6: At the moment, Semantika supports a subset of SPARQL 1.1 query expressions but they are enough to handle common query tasks. More query expressions will be added incrementally in the following releases.

The list below shows the supported expressions:

• SELECT (DISTINCT)
• FILTER
  • Relational Operators: =, <, >, <=, >=
  • Boolean Operators: AND, OR, NOT
  • Builtin Functions: BOUND, LANG, REGEX, STR
• OPTIONAL
• LIMIT, OFFSET

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