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 | |
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TDbQuery(const TDesC &, TDbTextComparison) | |
TDbTextComparison | Comparison() |
const TDesC & | Query() |
Private Attributes | |
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TDbTextComparison | iComparison |
const TDesC & | iQuery |
TDbQuery | ( | const TDesC & | aQuery, |
TDbTextComparison | aComparison = 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.
const TDesC & aQuery | The SQL string as a descriptor. |
TDbTextComparison aComparison = EDbCompareNormal | The type of text comparison to use in evaluation of the SQL. If not supplied, normal comparison is used. |
TDbTextComparison | Comparison | ( | ) | const [inline] |
Returns the text comparison mode for the query object.
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