TDbQuery Class Reference

class TDbQuery

A wrapper for an SQL string combined with a text comparison mode.

An instance of the class is used as a parameter to RDbView::Prepare(), RDbRowSet::FindL() and RDbRowConstraint::Open().

The evaluation of SQL queries or constraints depends on how Text columns are compared so every SQL string is accompanied by a member of the TDbTextComparison enumeration to indicate how comparison is done.

If the SQL string contains a LIKE clause with * (asterisks) wildcard then the characters between them must be no longer than length 255. If only one * exists then the length is taken from the start and to the end of the clause. However, if the clause contains a ? (question mark) wildcard within it then the characters between must be no longer than length 253.

TDbTextComparison

RDbView::Prepare()

RDbRowSet::FindL()

RDbRowConstraint::Open()

Public Member Functions
TDbQuery(const TDesC &, TDbTextComparison)
TDbTextComparison Comparison()
const TDesC &Query()
Private Attributes
TDbTextComparison iComparison
const TDesC &iQuery

Constructor & Destructor Documentation

TDbQuery(const TDesC &, TDbTextComparison)

TDbQuery(const TDesC &aQuery,
TDbTextComparisonaComparison = EDbCompareNormal
)[inline]

Constructs a query object from an SQL string and a text comparison mode.

Note that no copy is made of the descriptor passed; it is stored by reference in the query object.

Parameters

const TDesC & aQueryThe SQL string as a descriptor.
TDbTextComparison aComparison = EDbCompareNormalThe type of text comparison to use in evaluation of the SQL. If not supplied, normal comparison is used.

Member Functions Documentation

Comparison()

TDbTextComparison Comparison()const [inline]

Returns the text comparison mode for the query object.

The text comparison mode.

Query()

const TDesC &Query()const [inline]

Returns the SQL string in the query object.

A descriptor containing the SQL string.

Member Data Documentation

TDbTextComparison iComparison

TDbTextComparison iComparison[private]

const TDesC & iQuery

const TDesC &iQuery[private]