Volltextsuche in Blob möglichst schnell

[mkinzler]

Die Begrenzung ist wie gesagt 32765. Bei Firebird >=2.5 wird dann auch ein Textblob der kürzer ist wie ein VARCHAR-Feld behandelt

Zitat:

BLOB Subtype 1 Compatibility with VARCHAR
A. dos Santos Fernandes
(v.2.1) At various levels of evaluation, the engine now treats text BLOBs that are within the 32,765-byte string size limit as though they were VARCHARs. Operations that now allow text BLOBs to behave like strings are:
• Assignments, conversions and concatenations (|| operator)
• Operators = , <>, >, <, >=, <=, BETWEEN, IS [NOT] DISTINCT FROM
• Functions CAST, BIT_LENGTH, CHAR[ACTER]_LENGTH, OCTET_LENGTH, LEFT, RIGHT, HASH, LOWER, UPPER, LPAD, RPAD, TRIM, OVERLAY, REPLACE, POSITION, REVERSE, MINVALUE, MAXVALUE, SUBSTRING
• Existential predicators IN, ANY/SOME, ALL • Search predicators CONTAINING, STARTING [WITH], LIKE
• A LIST expression. Note that, prior to v.2.1.4, the last part of the result may be truncated, an effect that applies to native VARCHAR columns also.