Exec
sends a command to
the backend server. It's probably more desirable to use one
of the next two functions.
ExecStatusType PgConnection::Exec(const char* query)
Returns the result status of the command. The following status results can be expected:
PGRES_EMPTY_QUERY |
PGRES_COMMAND_OK, if the command was not a query |
PGRES_TUPLES_OK, if the query successfully returned tuples |
PGRES_COPY_OUT |
PGRES_COPY_IN |
PGRES_BAD_RESPONSE, if an unexpected response was received |
PGRES_NONFATAL_ERROR |
PGRES_FATAL_ERROR |
ExecCommandOk
sends a
non-query command (one that does not return rows) to the
backend server.
int PgConnection::ExecCommandOk(const char *query)
Returns true (1) if the command succeeds.
ExecTuplesOk
Sends a query
command (one that returns rows) to the backend server.
int PgConnection::ExecTuplesOk(const char *query)
Returns true (1) if the query succeeds.
ErrorMessage
returns the
last error message text.
const char *PgConnection::ErrorMessage()
Tuples
returns the number
of tuples (rows) in the query result.
int PgDatabase::Tuples() const
Fields
returns the number
of fields (rows) in each tuple of the query result.
int PgDatabase::Fields()
FieldName
returns the
field (column) name associated with the given field index.
Field indices start at 0.
const char *PgDatabase::FieldName(int field_num) const
FieldNum
returns the field
(column) index associated with the given field name.
int PgDatabase::FieldNum(const char* field_name) const
-1 is returned if the given name does not match any field.
FieldType
returns the
field type associated with the given field index. The
integer returned is an internal coding of the type. Field
indices start at 0.
Oid PgDatabase::FieldType(int field_num) const
FieldType
returns the
field type associated with the given field name. The
integer returned is an internal coding of the type. Field
indices start at 0.
Oid PgDatabase::FieldType(const char* field_name) const
FieldSize
returns the size
in bytes of the field associated with the given field
index. Field indices start at 0.
int PgDatabase::FieldSize(int field_num) const
Returns the space allocated for this field in a database tuple given the field number. In other words the size of the server's binary representation of the data type. -1 is returned if the field is variable size.
FieldSize
returns the size
in bytes of the field associated with the given field
index. Field indices start at 0.
int PgDatabase::FieldSize(const char *field_name) const
Returns the space allocated for this field in a database tuple given the field name. In other words the size of the server's binary representation of the data type. -1 is returned if the field is variable size.
GetValue
returns a single
field (column) value of one tuple of a PGresult. Tuple and field indices start
at 0.
const char *PgDatabase::GetValue(int tup_num, int field_num) const
For most queries, the value returned by GetValue
is a null-terminated string
representation of the attribute value. But if BinaryTuples
is true, the value returned
by GetValue
is the binary
representation of the type in the internal format of the
backend server (but not including the size word, if the
field is variable-length). It is then the programmer's
responsibility to cast and convert the data to the correct
C type. The pointer returned by GetValue
points to storage that is part
of the PGresult structure. One
should not modify it, and one must explicitly copy the
value into other storage if it is to be used past the
lifetime of the PGresult
structure itself. BinaryTuples
is not yet implemented.
GetValue
returns a single
field (column) value of one tuple of a PGresult. Tuple and field indices start
at 0.
const char *PgDatabase::GetValue(int tup_num, const char *field_name) const
For most queries, the value returned by GetValue
is a null-terminated string
representation of the attribute value. But if BinaryTuples
is true, the value returned
by GetValue
is the binary
representation of the type in the internal format of the
backend server (but not including the size word, if the
field is variable-length). It is then the programmer's
responsibility to cast and convert the data to the correct
C type. The pointer returned by GetValue
points to storage that is part
of the PGresult structure. One
should not modify it, and one must explicitly copy the
value into other storage if it is to be used past the
lifetime of the PGresult
structure itself. BinaryTuples
is not yet implemented.
GetLength
returns the
length of a field (column) in bytes. Tuple and field
indices start at 0.
int PgDatabase::GetLength(int tup_num, int field_num) const
This is the actual data length for the particular data
value, that is the size of the object pointed to by
GetValue
. Note that for
character-represented values, this size has little to do
with the binary size reported by PQfsize
.
GetLength
returns the
length of a field (column) in bytes. Tuple and field
indices start at 0.
int PgDatabase::GetLength(int tup_num, const char* field_name) const
This is the actual data length for the particular data
value, that is the size of the object pointed to by
GetValue
. Note that for
character-represented values, this size has little to do
with the binary size reported by PQfsize
.
GetIsNull
returns whether
a field has the null value.
bool GetIsNull(int tup_num, int field_num) const
Note that GetValue
will
return the empty string for null fields, not the NULL
pointer.
GetIsNull
returns whether
a field has the null value.
bool GetIsNull(int tup_num, const char *field_name) const
Note that GetValue
will
return the empty string for null fields, not the NULL
pointer.
DisplayTuples
prints out
all the tuples and, optionally, the attribute names to the
specified output stream.
void PgDatabase::DisplayTuples(FILE *out = 0, bool fillAlign = true, const char* fieldSep = "|", bool printHeader = true, bool quiet = false) const
This function is obsolescent.
PrintTuples
prints out all
the tuples and, optionally, the attribute names to the
specified output stream.
void PgDatabase::PrintTuples(FILE *out = 0, bool printAttName = true, bool terseOutput = false, bool fillAlign = false) const
This function is obsolescent.
CmdTuples
returns the
number of rows affected after an INSERT, UPDATE, or
DELETE. If the command was anything
else, it returns -1.
int PgDatabase::CmdTuples() const
OidStatus
const char *PgDatabase::OidStatus() const