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QPSQL: Add support for multiple result sets

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This change adds support for multiple result sets in PostgreSQL.

[Important Behavior Changes] The QPSQL driver now supports multiple
result sets. Since QPSQL previously did not support multiple result
sets, there may be some compatibility issues with the existing code
that executed several queries as one and were expecting to get
the results of the last one. In this case use QSqlQuery::nextResult()
to move to the last result set.

[ChangeLog][QtSql][QPSQL] Added support for multiple result sets

Change-Id: I2bfc91f512c4dac83116f3aa42833839a6da084c
Reviewed-by: Andy Shaw <andy.shaw@qt.io>
This commit is contained in:
Robert Szefner 2017-11-10 08:35:40 +01:00 committed by Robert Szefner
parent cf35bc21c0
commit 6d0c8825f9
2 changed files with 96 additions and 5 deletions
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49
src/plugins/sqldrivers/psql/qsql_psql.cpp
View File

@ -152,6 +152,7 @@ protected:
bool fetchFirst() override;
bool fetchLast() override;
bool fetchNext() override;
bool nextResult() override;
QVariant data(int i) override;
bool isNull(int field) override;
bool reset (const QString &query) override;
@ -325,6 +326,7 @@ public:
void deallocatePreparedStmt();
PGresult *result;
QList<PGresult*> nextResultSets;
int currentSize;
bool canFetchMoreRows;
StatementId stmtId;
@ -479,6 +481,8 @@ void QPSQLResult::cleanup()
if (d->result)
PQclear(d->result);
d->result = nullptr;
while (!d->nextResultSets.isEmpty())
PQclear(d->nextResultSets.takeFirst());
if (d->stmtId != InvalidStatementId)
d->drv_d_func()->finishQuery(d->stmtId);
d->stmtId = InvalidStatementId;
@ -608,6 +612,39 @@ bool QPSQLResult::fetchNext()
return true;
}
bool QPSQLResult::nextResult()
{
Q_D(QPSQLResult);
if (!isActive())
return false;
setAt(QSql::BeforeFirstRow);
if (isForwardOnly()) {
if (d->canFetchMoreRows) {
// Skip all rows from current result set
while (d->result && PQresultStatus(d->result) == PGRES_SINGLE_TUPLE) {
PQclear(d->result);
d->result = d->drv_d_func()->getResult(d->stmtId);
}
d->canFetchMoreRows = false;
// Check for unexpected errors
if (d->result && PQresultStatus(d->result) == PGRES_FATAL_ERROR)
return d->processResults();
}
// Fetch first result from next result set
if (d->result)
PQclear(d->result);
d->result = d->drv_d_func()->getResult(d->stmtId);
return d->processResults();
}
if (d->result)
PQclear(d->result);
d->result = d->nextResultSets.isEmpty() ? nullptr : d->nextResultSets.takeFirst();
return d->processResults();
}
QVariant QPSQLResult::data(int i)
{
Q_D(const QPSQLResult);
@ -729,6 +766,11 @@ bool QPSQLResult::reset (const QString& query)
setForwardOnly(d->drv_d_func()->setSingleRowMode());
d->result = d->drv_d_func()->getResult(d->stmtId);
if (!isForwardOnly()) {
// Fetch all result sets right away
while (PGresult *nextResultSet = d->drv_d_func()->getResult(d->stmtId))
d->nextResultSets.append(nextResultSet);
}
return d->processResults();
}
@ -914,6 +956,11 @@ bool QPSQLResult::exec()
setForwardOnly(d->drv_d_func()->setSingleRowMode());
d->result = d->drv_d_func()->getResult(d->stmtId);
if (!isForwardOnly()) {
// Fetch all result sets right away
while (PGresult *nextResultSet = d->drv_d_func()->getResult(d->stmtId))
d->nextResultSets.append(nextResultSet);
}
return d->processResults();
}
@ -1132,6 +1179,7 @@ bool QPSQLDriver::hasFeature(DriverFeature f) const
case LastInsertId:
case LowPrecisionNumbers:
case EventNotifications:
case MultipleResultSets:
case BLOB:
return true;
case PreparedQueries:
@ -1141,7 +1189,6 @@ bool QPSQLDriver::hasFeature(DriverFeature f) const
case NamedPlaceholders:
case SimpleLocking:
case FinishQuery:
case MultipleResultSets:
case CancelQuery:
return false;
case Unicode:

52
tests/auto/sql/kernel/qsqlquery/tst_qsqlquery.cpp
View File

@ -2892,8 +2892,8 @@ void tst_QSqlQuery::nextResult()
QSqlDatabase db = QSqlDatabase::database( dbName );
CHECK_DATABASE( db );
const QSqlDriver::DbmsType dbType = tst_Databases::getDatabaseType(db);
if ( !db.driver()->hasFeature( QSqlDriver::MultipleResultSets ) || !db.driver()->hasFeature( QSqlDriver::BatchOperations ) )
QSKIP( "DBMS does not support multiple result sets or batch operations");
if (!db.driver()->hasFeature(QSqlDriver::MultipleResultSets))
QSKIP("DBMS does not support multiple result sets");
QSqlQuery q( db );
@ -3006,7 +3006,10 @@ void tst_QSqlQuery::nextResult()
// Stored procedure with multiple result sets
const QString procName(qTableName("proc_more_res", __FILE__, db));
q.exec( QString( "DROP PROCEDURE %1;" ).arg( procName ) );
if (dbType == QSqlDriver::PostgreSQL)
q.exec(QString("DROP FUNCTION %1(refcursor, refcursor);").arg(procName));
else
q.exec(QString("DROP PROCEDURE %1;").arg(procName));
if (dbType == QSqlDriver::MySqlServer)
QVERIFY_SQL( q, exec( QString( "CREATE PROCEDURE %1()"
@ -3024,6 +3027,16 @@ void tst_QSqlQuery::nextResult()
"\nOPEN cursor1;"
"\nOPEN cursor2;"
"\nEND p1" ).arg( procName ).arg( tableName ).arg( tableName ) ) );
else if (dbType == QSqlDriver::PostgreSQL)
QVERIFY_SQL(q, exec(QString("CREATE FUNCTION %1(ref1 refcursor, ref2 refcursor)"
"\nRETURNS SETOF refcursor AS $$"
"\nBEGIN"
"\nOPEN ref1 FOR SELECT id, text FROM %2;"
"\nRETURN NEXT ref1;"
"\nOPEN ref2 FOR SELECT empty, num, text, id FROM %2;"
"\nRETURN NEXT ref2;"
"\nEND;"
"\n$$ LANGUAGE plpgsql").arg(procName).arg(tableName)));
else
QVERIFY_SQL( q, exec( QString( "CREATE PROCEDURE %1"
"\nAS"
@ -3033,10 +3046,32 @@ void tst_QSqlQuery::nextResult()
if (dbType == QSqlDriver::MySqlServer || dbType == QSqlDriver::DB2) {
q.setForwardOnly( true );
QVERIFY_SQL( q, exec( QString( "CALL %1()" ).arg( procName ) ) );
} else if (dbType == QSqlDriver::PostgreSQL) {
// Returning multiple result sets from PostgreSQL stored procedure:
// http://sqlines.com/postgresql/how-to/return_result_set_from_stored_procedure
QVERIFY_SQL(q, exec(QString("BEGIN;"
"SELECT %1('cur1', 'cur2');"
"FETCH ALL IN cur1;"
"FETCH ALL IN cur2;"
"COMMIT;").arg(procName)));
} else {
QVERIFY_SQL( q, exec( QString( "EXEC %1" ).arg( procName ) ) );
}
if (dbType == QSqlDriver::PostgreSQL) {
// First result set - start of transaction
QVERIFY(!q.isSelect());
QCOMPARE(q.numRowsAffected(), 0);
QVERIFY(q.nextResult());
// Second result set contains cursor names
QVERIFY(q.isSelect());
QVERIFY(q.next());
QCOMPARE(q.value(0).toString(), "cur1");
QVERIFY(q.next());
QCOMPARE(q.value(0).toString(), "cur2");
QVERIFY(q.nextResult());
}
for ( int i = 0; i < 4; i++ ) {
QVERIFY_SQL( q, next() );
QCOMPARE( q.value( 0 ).toInt(), i+1 );
@ -3061,12 +3096,21 @@ void tst_QSqlQuery::nextResult()
QVERIFY( !q.isSelect() ); // ... but it's not a select
QCOMPARE( q.numRowsAffected(), 0 ); // ... and no rows are affected (at least not with this procedure)
}
if (dbType == QSqlDriver::PostgreSQL) {
// Last result set - commit transaction
QVERIFY(q.nextResult());
QVERIFY(!q.isSelect());
QCOMPARE(q.numRowsAffected(), 0);
}
QVERIFY( !q.nextResult() );
QVERIFY( !q.isActive() );
q.exec( QString( "DROP PROCEDURE %1;" ).arg( procName ) );
if (dbType == QSqlDriver::PostgreSQL)
q.exec(QString("DROP FUNCTION %1(refcursor, refcursor);").arg(procName));
else
q.exec(QString("DROP PROCEDURE %1;").arg(procName));
}