diff options
Diffstat (limited to 'src/sql')
| -rw-r--r-- | src/sql/kernel/qsqldriver.cpp | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/sql/kernel/qsqldriver.cpp b/src/sql/kernel/qsqldriver.cpp index ac51941f43..ad5207cf6e 100644 --- a/src/sql/kernel/qsqldriver.cpp +++ b/src/sql/kernel/qsqldriver.cpp @@ -472,6 +472,17 @@ QString QSqlDriver::stripDelimiters(const QString &identifier, IdentifierType ty This method can be used to manipulate tables without having to worry about database-dependent SQL dialects. For non-prepared statements, the values will be properly escaped. + + In the WHERE statement, each non-null field of \a rec specifies a + filter condition of equality to the field value, or if prepared, a + placeholder. However, prepared or not, a null field specifies the + condition IS NULL and never introduces a placeholder. The + application must not attempt to bind data for the null field during + execution. The field must be set to some non-null value if a + placeholder is desired. Furthermore, since non-null fields specify + equality conditions and SQL NULL is not equal to anything, even + itself, it is generally not useful to bind a null to a placeholder. + */ QString QSqlDriver::sqlStatement(StatementType type, const QString &tableName, const QSqlRecord &rec, bool preparedStatement) const |