s_object *
RS_PostgreSQL_getResult(Con_Handle * conHandle)
{
S_EVALUATOR RS_DBI_connection * con;
S_EVALUATOR RS_DBI_resultSet * result;
PGconn *my_connection;
Res_Handle *rsHandle;
Sint res_id;
PGresult *my_result;
con = RS_DBI_getConnection(conHandle);
my_connection = (PGconn *) con->drvConnection;
if (con->num_res > 0) {
res_id = (Sint) con->resultSetIds[0];
rsHandle = RS_DBI_asResHandle(MGR_ID(conHandle), CON_ID(conHandle), res_id);
result = RS_DBI_getResultSet(rsHandle);
if (result->completed == 0) {
RS_DBI_errorMessage("connection with pending rows, close resultSet before continuing", RS_DBI_ERROR);
}
else {
RS_PostgreSQL_closeResultSet(rsHandle);
}
}
my_result = PQgetResult(my_connection);
if(my_result == NULL)
return S_NULL_ENTRY;
if (strcmp(PQresultErrorMessage(my_result), "") != 0) {
char *errResultMsg;
const char *omsg;
size_t len;
omsg = PQerrorMessage(my_connection);
len = strlen(omsg);
errResultMsg = malloc(len + 80); /* 80 should be larger than the length of "could not ..."*/
snprintf(errResultMsg, len + 80, "could not Retrieve the result : %s", omsg);
RS_DBI_errorMessage(errResultMsg, RS_DBI_ERROR);
free(errResultMsg);
/* Frees the storage associated with a PGresult.
* void PQclear(PGresult *res); */
PQclear(my_result);
}
/* we now create the wrapper and copy values */
PROTECT(rsHandle = RS_DBI_allocResultSet(conHandle));
result = RS_DBI_getResultSet(rsHandle);
result->drvResultSet = (void *) my_result;
result->rowCount = (Sint) 0;
result->isSelect = 0;
result->rowsAffected = 0;
result->completed = 1;
UNPROTECT(1);
return rsHandle;
}
SEXP RS_MySQL_resultSetInfo(SEXP rsHandle) {
RS_DBI_resultSet *result;
SEXP output, flds;
int n = 6;
char *rsDesc[] = {"statement", "isSelect", "rowsAffected",
"rowCount", "completed", "fieldDescription"};
SEXPTYPE rsType[] = {STRSXP, INTSXP, INTSXP,
INTSXP, INTSXP, VECSXP};
int rsLen[] = {1, 1, 1, 1, 1, 1};
result = RS_DBI_getResultSet(rsHandle);
flds = R_NilValue;
output = RS_DBI_createNamedList(rsDesc, rsType, rsLen, n);
SET_LST_CHR_EL(output,0,0,mkChar(result->statement));
LST_INT_EL(output,1,0) = result->isSelect;
LST_INT_EL(output,2,0) = result->rowsAffected;
LST_INT_EL(output,3,0) = result->rowCount;
LST_INT_EL(output,4,0) = result->completed;
if(flds != R_NilValue)
SET_ELEMENT(LST_EL(output, 5), (int) 0, flds);
return output;
}
SEXP RS_MySQL_nextResultSet(SEXP conHandle) {
RS_DBI_resultSet *result;
SEXP rsHandle;
int num_fields, is_select;
RS_DBI_connection* con = RS_DBI_getConnection(conHandle);
MYSQL* my_connection = con->drvConnection;
int rc = mysql_next_result(my_connection);
if (rc < 0) {
error("no more result sets");
} else if (rc > 0){
error("error in getting next result set");
}
/* the following comes verbatim from RS_MySQL_exec() */
MYSQL_RES* my_result = mysql_use_result(my_connection);
if (!my_result)
my_result = NULL;
num_fields = mysql_field_count(my_connection);
is_select = TRUE;
if (!my_result) {
if (num_fields > 0) {
error("error in getting next result set");
} else {
is_select = FALSE;
}
}
/* we now create the wrapper and copy values */
rsHandle = RS_DBI_allocResultSet(conHandle);
result = RS_DBI_getResultSet(rsHandle);
result->statement = RS_DBI_copyString("<UNKNOWN>");
result->drvResultSet = (void *) my_result;
result->rowCount = (int) 0;
result->isSelect = is_select;
if (!is_select){
result->rowsAffected = (int) mysql_affected_rows(my_connection);
result->completed = 1;
} else {
result->rowsAffected = (int) -1;
result->completed = 0;
}
if (is_select)
result->fields = RS_MySQL_createDataMappings(rsHandle);
return rsHandle;
}
SEXP rmysql_fields_info(SEXP rsHandle) {
RS_DBI_resultSet* result = RS_DBI_getResultSet(rsHandle);
RMySQLFields* flds = result->fields;
int n = flds->num_fields;
// Allocate output
SEXP output = PROTECT(allocVector(VECSXP, 4));
SEXP output_nms = PROTECT(allocVector(STRSXP, 4));
SET_NAMES(output, output_nms);
UNPROTECT(1);
SET_STRING_ELT(output_nms, 0, mkChar("name"));
SEXP names = PROTECT(allocVector(STRSXP, n));
for (int j = 0; j < n; j++) {
SET_STRING_ELT(names, j, mkChar(flds->name[j]));
}
SET_VECTOR_ELT(output, 0, names);
UNPROTECT(1);
SET_STRING_ELT(output_nms, 1, mkChar("Sclass"));
SEXP sclass = PROTECT(allocVector(STRSXP, n));
for (int j = 0; j < n; j++) {
const char* type = type2char(flds->Sclass[j]);
SET_STRING_ELT(sclass, j, mkChar(type));
}
SET_VECTOR_ELT(output, 1, sclass);
UNPROTECT(1);
SET_STRING_ELT(output_nms, 2, mkChar("type"));
SEXP types = PROTECT(allocVector(STRSXP, n));
for (int j = 0; j < n; j++) {
char* type = rmysql_type(flds->type[j]);
SET_STRING_ELT(types, j, mkChar(type));
}
SET_VECTOR_ELT(output, 2, types);
UNPROTECT(1);
SET_STRING_ELT(output_nms, 3, mkChar("length"));
SEXP lens = PROTECT(allocVector(INTSXP, n));
for (int j = 0; j < n; j++) {
INTEGER(lens)[j] = flds->length[j];
}
SET_VECTOR_ELT(output, 3, lens);
UNPROTECT(1);
UNPROTECT(1);
return output;
}
void RS_DBI_freeResultSet(SEXP rsHandle) {
RS_DBI_connection* con = RS_DBI_getConnection(rsHandle);
RS_DBI_resultSet* result = RS_DBI_getResultSet(rsHandle);
if(result->drvResultSet) {
error("internal error in RS_DBI_freeResultSet: non-freed result->drvResultSet (some memory leaked)");
}
if (result->statement)
free(result->statement);
if (result->fields)
rmysql_fields_free(result->fields);
free(result);
result = NULL;
/* update connection's resultSet table */
int indx = RS_DBI_lookup(con->resultSetIds, con->length, RES_ID(rsHandle));
RS_DBI_freeEntry(con->resultSetIds, indx);
con->resultSets[indx] = NULL;
con->num_res -= 1;
}
SEXP RS_MySQL_closeResultSet(SEXP resHandle) {
RS_DBI_resultSet *result;
MYSQL_RES *my_result;
result = RS_DBI_getResultSet(resHandle);
my_result = (MYSQL_RES *) result->drvResultSet;
if(my_result){
// we need to flush any possibly remaining rows (see Manual Ch 20 p358)
MYSQL_ROW row;
while((row = mysql_fetch_row(result->drvResultSet)))
;
}
mysql_free_result(my_result);
// need to NULL drvResultSet, otherwise can't free the rsHandle
result->drvResultSet = (void *) NULL;
RS_DBI_freeResultSet(resHandle);
return ScalarLogical(TRUE);
}
RS_DBI_fields *
RS_PostgreSQL_createDataMappings(Res_Handle * rsHandle)
{
PGresult *my_result;
RS_DBI_connection *con;
RS_DBI_resultSet *result;
RS_DBI_fields *flds;
int j, num_fields, internal_type;
char errMsg[128];
result = RS_DBI_getResultSet(rsHandle);
my_result = (PGresult *) result->drvResultSet;
con = RS_DBI_getConnection(rsHandle);
num_fields = PQnfields(my_result);
flds = RS_DBI_allocFields(num_fields); /* this returns malloced data (not from R) */
char buff[1000]; /* Buffer to hold the sql query to check whether the given column is nullable */
PGconn *conn;
PGresult *res;
conn = (PGconn *) con->drvConnection;
for (j = 0; j < num_fields; j++) {
flds->name[j] = RS_DBI_copyString(PQfname(my_result, j));
flds->type[j] = (int) PQftype(my_result, j);
flds->length[j] = (Sint) PQfsize(my_result, j);
/* NOTE: PQfmod is -1 incase of no information */
flds->precision[j] = (Sint) PQfmod(my_result, j);
flds->scale[j] = (Sint) - 1;
/* PQftablecol returns the column number (within its table) of
* the column making up the specified query result column.Zero
* is returned if the column number is out of range, or if the
* specified column is not a simple reference to a table
* column, or when using pre-3.0 protocol. So
* "if(PQftablecol(my_result,j) !=0)" checks whether the
* particular colomn in the result set is column of table or
* not. Or else there is no meaning in checking whether a
* column is nullable or not if it does not belong to the
* table.
*/
flds->nullOk[j] = (Sint) INT_MIN; /* This should translate to NA in R */
if (PQftablecol(my_result, j) != 0) {
/* Code to find whether a row can be nullable or not */
/* we might better just store the table id and column number
for lazy evaluation at dbColumnInfo call*/
/* although the database structure can change, we are not in transaction anyway
and there is no guarantee in current code */
snprintf(buff, 1000, "select attnotnull from pg_attribute where attrelid=%d and attnum='%d'",
PQftable(my_result, j), PQftablecol(my_result, j));
res = PQexec(conn, buff);
if (res && (PQntuples(res) > 0)) {
const char * attnotnull = PQgetvalue(res, 0, 0);
if(strcmp(attnotnull, "f") == 0) {
flds->nullOk[j] = (Sint) 1; /* nollOK is TRUE when attnotnull is f*/
}
if(strcmp(attnotnull, "t") == 0) {
flds->nullOk[j] = (Sint) 0; /* nollOK is FALSE when attnotnull is t*/
}
}
PQclear(res);
}
internal_type = (int) PQftype(my_result, j);
switch (internal_type) {
case BOOLOID:
flds->Sclass[j] = LOGICAL_TYPE;
break;
case BPCHAROID:
flds->Sclass[j] = CHARACTER_TYPE;
flds->isVarLength[j] = (Sint) 0;
break;
case VARCHAROID:
case TEXTOID:
case BYTEAOID:
case NAMEOID:
case MACADDROID:
case INETOID:
flds->Sclass[j] = CHARACTER_TYPE;
flds->isVarLength[j] = (Sint) 1;
break;
case INT2OID:
case INT4OID:
case OIDOID:
flds->Sclass[j] = INTEGER_TYPE;
break;
case INT8OID:
if (sizeof(Sint) >= 8) {
flds->Sclass[j] = INTEGER_TYPE;
}
else {
flds->Sclass[j] = NUMERIC_TYPE;
}
break;
case NUMERICOID:
case FLOAT8OID:
case FLOAT4OID:
flds->Sclass[j] = NUMERIC_TYPE;
break;
case DATEOID:
case TIMEOID:
case TIMETZOID:
case TIMESTAMPOID:
case TIMESTAMPTZOID:
case INTERVALOID:
flds->Sclass[j] = CHARACTER_TYPE;
/*flds->isVarLength[j] = (Sint) 1; */
break;
default:
flds->Sclass[j] = CHARACTER_TYPE;
flds->isVarLength[j] = (Sint) 1;
snprintf(buff, 1000, "select typname, typcategory from pg_type where oid = %d", internal_type);
res = PQexec(conn, buff);
if (res) {
char * typename;
char * typecat;
int ntuples;
ntuples = PQntuples(res);
if(ntuples == 1) {
typename = PQgetvalue(res, 0, 0);
typecat = PQgetvalue(res, 0, 1);
if(*typecat == 'E') { /* This is enum, ok */
} else if(*typecat == 'A') { /*This is array, ok */
} else {
snprintf(errMsg, 128, "unrecognized PostgreSQL field type %s (id:%d) in column %d", typename, internal_type, j);
RS_DBI_errorMessage(errMsg, RS_DBI_WARNING);
}
} else {
snprintf(errMsg, 128, "oid: %d, ntuples: %d", internal_type, ntuples);
RS_DBI_errorMessage(errMsg, RS_DBI_WARNING);
}
PQclear(res);
} else {
Res_Handle *
RS_PostgreSQL_exec(Con_Handle * conHandle, s_object * statement)
{
S_EVALUATOR RS_DBI_connection * con;
Res_Handle *rsHandle;
RS_DBI_resultSet *result;
PGconn *my_connection;
PGresult *my_result;
Sint res_id, is_select=0;
char *dyn_statement;
con = RS_DBI_getConnection(conHandle);
my_connection = (PGconn *) con->drvConnection;
dyn_statement = RS_DBI_copyString(CHR_EL(statement, 0));
/* Do we have a pending resultSet in the current connection?
* PostgreSQL only allows one resultSet per connection.
*/
if (con->num_res > 0) {
res_id = (Sint) con->resultSetIds[0]; /* recall, PostgreSQL has only 1 res */
rsHandle = RS_DBI_asResHandle(MGR_ID(conHandle), CON_ID(conHandle), res_id);
result = RS_DBI_getResultSet(rsHandle);
if (result->completed == 0) {
free(dyn_statement);
RS_DBI_errorMessage("connection with pending rows, close resultSet before continuing", RS_DBI_ERROR);
}
else {
RS_PostgreSQL_closeResultSet(rsHandle);
}
}
/* Here is where we actually run the query */
/* Example: PGresult *PQexec(PGconn *conn, const char *command); */
my_result = PQexec(my_connection, dyn_statement);
if (my_result == NULL) {
char *errMsg;
const char *omsg;
size_t len;
omsg = PQerrorMessage(my_connection);
len = strlen(omsg);
free(dyn_statement);
errMsg = R_alloc(len + 80, 1); /* 80 should be larger than the length of "could not ..."*/
snprintf(errMsg, len + 80, "could not run statement: %s", omsg);
RS_DBI_errorMessage(errMsg, RS_DBI_ERROR);
}
/* ExecStatusType PQresultStatus(const PGresult *res); */
if (PQresultStatus(my_result) == PGRES_TUPLES_OK) {
is_select = (Sint) TRUE;
}
if (PQresultStatus(my_result) == PGRES_COMMAND_OK) {
is_select = (Sint) FALSE;
}
/* char *PQresultErrorMessage(const PGresult *res); */
if (strcmp(PQresultErrorMessage(my_result), "") != 0) {
char *errResultMsg;
const char *omsg;
size_t len;
omsg = PQerrorMessage(my_connection);
len = strlen(omsg);
errResultMsg = R_alloc(len + 80, 1); /* 80 should be larger than the length of "could not ..."*/
snprintf(errResultMsg, len + 80, "could not Retrieve the result : %s", omsg);
/* Frees the storage associated with a PGresult.
* void PQclear(PGresult *res); */
PQclear(my_result);
free(dyn_statement);
RS_DBI_errorMessage(errResultMsg, RS_DBI_ERROR);
}
/* we now create the wrapper and copy values */
PROTECT(rsHandle = RS_DBI_allocResultSet(conHandle));
result = RS_DBI_getResultSet(rsHandle);
result->statement = RS_DBI_copyString(dyn_statement);
result->drvResultSet = (void *) my_result;
result->rowCount = (Sint) 0;
result->isSelect = is_select;
/* Returns the number of rows affected by the SQL command.
* char *PQcmdTuples(PGresult *res);
*/
if (!is_select) {
result->rowsAffected = (Sint) atoi(PQcmdTuples(my_result));
result->completed = 1;
}
else {
result->rowsAffected = (Sint) - 1;
result->completed = 0;
}
if (is_select) {
result->fields = RS_PostgreSQL_createDataMappings(rsHandle);
}
free(dyn_statement);
UNPROTECT(1);
return rsHandle;
}
RMySQLFields* RS_MySQL_createDataMappings(SEXP rsHandle) {
// Fetch MySQL field descriptions
RS_DBI_resultSet* result = RS_DBI_getResultSet(rsHandle);
MYSQL_RES* my_result = result->drvResultSet;
MYSQL_FIELD* select_dp = mysql_fetch_fields(my_result);
int num_fields = mysql_num_fields(my_result);
// Allocate memory for output object
RMySQLFields* flds = malloc(sizeof(RMySQLFields));
if (!flds) {
error("Could not allocate memory for database fields");
}
flds->num_fields = num_fields;
flds->name = calloc(num_fields, sizeof(char *));
flds->type = calloc(num_fields, sizeof(int));
flds->length = calloc(num_fields, sizeof(int));
flds->precision = calloc(num_fields, sizeof(int));
flds->scale = calloc(num_fields, sizeof(int));
flds->nullOk = calloc(num_fields, sizeof(int));
flds->isVarLength = calloc(num_fields, sizeof(int));
flds->Sclass = calloc(num_fields, sizeof(SEXPTYPE));
/* WARNING: TEXT fields are represented as BLOBS (sic),
* not VARCHAR or some kind of string type. More troublesome is the
* fact that a TEXT fields can be BINARY to indicate case-sensitivity.
* The bottom line is that MySQL has a serious deficiency re: text
* types (IMHO). A binary object (in SQL92, X/SQL at least) can
* store all kinds of non-ASCII, non-printable stuff that can
* potentially screw up S and R CHARACTER_TYPE. We are on thin ice.
*
* I'm aware that I'm introducing a potential bug here by following
* the MySQL convention of treating BLOB's as TEXT (I'm symplifying
* in order to properly handle commonly-found TEXT fields, at the
* risk of core dumping when bona fide Binary objects are being
* retrieved.
*
* Possible workaround: if strlen() of the field equals the
* MYSQL_FIELD->length for all rows, then we are probably(?) safe
* in considering TEXT a character type (non-binary).
*/
for (int j = 0; j < num_fields; j++){
/* First, save the name, MySQL internal field name, type, length, etc. */
flds->name[j] = RS_DBI_copyString(select_dp[j].name);
flds->type[j] = select_dp[j].type; /* recall that these are enum*/
flds->length[j] = select_dp[j].length;
flds->precision[j] = select_dp[j].length;
flds->scale[j] = select_dp[j].decimals;
flds->nullOk[j] = (!IS_NOT_NULL(select_dp[j].flags));
int internal_type = select_dp[j].type;
switch(internal_type) {
case FIELD_TYPE_VAR_STRING:
case FIELD_TYPE_STRING:
flds->Sclass[j] = STRSXP;
flds->isVarLength[j] = (int) 1;
break;
case FIELD_TYPE_TINY: /* 1-byte TINYINT */
case FIELD_TYPE_SHORT: /* 2-byte SMALLINT */
case FIELD_TYPE_INT24: /* 3-byte MEDIUMINT */
flds->Sclass[j] = INTSXP;
case FIELD_TYPE_LONG: /* 4-byte INTEGER */
/* if unsigned, turn into numeric (may be too large for ints/long)*/
if(select_dp[j].flags & UNSIGNED_FLAG) {
warning("Unsigned INTEGER in col %d imported as numeric", j);
flds->Sclass[j] = REALSXP;
} else {
flds->Sclass[j] = INTSXP;
}
break;
case FIELD_TYPE_LONGLONG: /* 8-byte BIGINT */
flds->Sclass[j] = REALSXP;
break;
#if defined(MYSQL_VERSION_ID) && MYSQL_VERSION_ID >= 50003 /* 5.0.3 */
case FIELD_TYPE_BIT:
if(flds->precision[j] <= sizeof(int)) {
/* can R int hold the bytes? */
flds->Sclass[j] = INTSXP;
} else {
flds->Sclass[j] = STRSXP;
warning(
"BIT field in column %d too long (%d bits) for an R integer (imported as character)",
j+1, flds->precision[j]
);
}
break;
#endif
flds->Sclass[j] = REALSXP;
break;
case FIELD_TYPE_DECIMAL:
#if defined(MYSQL_VERSION_ID) && MYSQL_VERSION_ID >= 50003 /* 5.0.3 */
case FIELD_TYPE_NEWDECIMAL:
#endif
warning("Decimal MySQL column %d imported as numeric", j);
flds->Sclass[j] = REALSXP;
break;
case FIELD_TYPE_FLOAT:
case FIELD_TYPE_DOUBLE:
flds->Sclass[j] = REALSXP;
break;
case FIELD_TYPE_BLOB: /* TODO: how should we bring large ones*/
case FIELD_TYPE_TINY_BLOB:
case FIELD_TYPE_MEDIUM_BLOB:
case FIELD_TYPE_LONG_BLOB:
flds->Sclass[j] = STRSXP; /* Grr! Hate this! */
flds->isVarLength[j] = (int) 1;
break;
case FIELD_TYPE_DATE:
case FIELD_TYPE_TIME:
case FIELD_TYPE_DATETIME:
case FIELD_TYPE_YEAR:
case FIELD_TYPE_NEWDATE:
flds->Sclass[j] = STRSXP;
flds->isVarLength[j] = (int) 1;
break;
case FIELD_TYPE_ENUM:
flds->Sclass[j] = STRSXP; /* see the MySQL ref. manual */
flds->isVarLength[j] = (int) 1;
break;
case FIELD_TYPE_SET:
flds->Sclass[j] = STRSXP;
flds->isVarLength[j] = (int) 0;
break;
default:
flds->Sclass[j] = STRSXP;
flds->isVarLength[j] = (int) 1;
warning("unrecognized MySQL field type %d in column %d imported as character",
internal_type, j);
break;
}
}
return flds;
}
// output is a named list
SEXP RS_MySQL_fetch(SEXP rsHandle, SEXP max_rec) {
MySQLDriver *mgr;
RS_DBI_resultSet *result;
RMySQLFields* flds;
MYSQL_RES *my_result;
MYSQL_ROW row;
SEXP output, s_tmp;
unsigned long *lens;
int i, j, null_item, expand;
int completed;
SEXPTYPE *fld_Sclass;
int num_rec;
int num_fields;
result = RS_DBI_getResultSet(rsHandle);
flds = result->fields;
if(!flds)
error("corrupt resultSet, missing fieldDescription");
num_rec = asInteger(max_rec);
expand = (num_rec < 0); // dyn expand output to accommodate all rows
if(expand || num_rec == 0){
mgr = rmysql_driver();
num_rec = mgr->fetch_default_rec;
}
num_fields = flds->num_fields;
PROTECT(output = NEW_LIST((int) num_fields));
RS_DBI_allocOutput(output, flds, num_rec, 0);
fld_Sclass = flds->Sclass;
// actual fetching....
my_result = (MYSQL_RES *) result->drvResultSet;
completed = (int) 0;
for(i = 0; ; i++){
if(i==num_rec){ // exhausted the allocated space
if(expand){ // do we extend or return the records fetched so far
num_rec = 2 * num_rec;
RS_DBI_allocOutput(output, flds, num_rec, expand);
}
else
break; // okay, no more fetching for now
}
row = mysql_fetch_row(my_result);
if(row==NULL){ // either we finish or we encounter an error
unsigned int err_no;
RS_DBI_connection *con;
con = RS_DBI_getConnection(rsHandle);
err_no = mysql_errno((MYSQL *) con->drvConnection);
completed = (int) (err_no ? -1 : 1);
break;
}
lens = mysql_fetch_lengths(my_result);
for(j = 0; j < num_fields; j++){
null_item = (row[j] == NULL);
switch((int)fld_Sclass[j]){
case INTSXP:
if(null_item)
NA_SET(&(LST_INT_EL(output,j,i)), INTSXP);
else
LST_INT_EL(output,j,i) = (int) atol(row[j]);
break;
case STRSXP:
// BUG: I need to verify that a TEXT field (which is stored as
// a BLOB by MySQL!) is indeed char and not a true
// Binary obj (MySQL does not truly distinguish them). This
// test is very gross.
if(null_item)
SET_LST_CHR_EL(output,j,i,NA_STRING);
else {
if((size_t) lens[j] != strlen(row[j])){
warning("internal error: row %d field %d truncated", i, j);
}
SET_LST_CHR_EL(output,j,i,mkChar(row[j]));
}
break;
case REALSXP:
if(null_item)
NA_SET(&(LST_NUM_EL(output,j,i)), REALSXP);
else
LST_NUM_EL(output,j,i) = (double) atof(row[j]);
break;
default: // error, but we'll try the field as character (!)
if(null_item)
SET_LST_CHR_EL(output,j,i, NA_STRING);
else {
warning("unrecognized field type %d in column %d", fld_Sclass[j], j);
SET_LST_CHR_EL(output,j,i,mkChar(row[j]));
}
break;
}
}
}
// actual number of records fetched
if(i < num_rec){
num_rec = i;
// adjust the length of each of the members in the output_list
for(j = 0; j<num_fields; j++){
s_tmp = LST_EL(output,j);
PROTECT(SET_LENGTH(s_tmp, num_rec));
SET_ELEMENT(output, j, s_tmp);
UNPROTECT(1);
}
}
if(completed < 0)
warning("error while fetching rows");
result->rowCount += num_rec;
result->completed = (int) completed;
UNPROTECT(1);
return output;
}
/* Execute (currently) one sql statement (INSERT, DELETE, SELECT, etc.),
* set coercion type mappings between the server internal data types and
* S classes. Returns an S handle to a resultSet object.
*/
SEXP RS_MySQL_exec(SEXP conHandle, SEXP statement) {
RS_DBI_connection *con;
SEXP rsHandle;
RS_DBI_resultSet *result;
MYSQL *my_connection;
MYSQL_RES *my_result;
int num_fields, state;
int res_id, is_select;
char *dyn_statement;
con = RS_DBI_getConnection(conHandle);
my_connection = (MYSQL *) con->drvConnection;
dyn_statement = RS_DBI_copyString(CHR_EL(statement,0));
/* Do we have a pending resultSet in the current connection?
* MySQL only allows one resultSet per connection.
*/
if(con->num_res>0){
res_id = (int) con->resultSetIds[0]; /* recall, MySQL has only 1 res */
rsHandle = RS_DBI_asResHandle(MGR_ID(conHandle),
CON_ID(conHandle), res_id);
result = RS_DBI_getResultSet(rsHandle);
if(result->completed == 0){
free(dyn_statement);
error("connection with pending rows, close resultSet before continuing");
}
else
RS_MySQL_closeResultSet(rsHandle);
}
/* Here is where we actually run the query */
state = mysql_query(my_connection, dyn_statement);
if(state) {
error("could not run statement: %s", mysql_error(my_connection));
}
/* Do we need output column/field descriptors? Only for SELECT-like
* statements. The MySQL reference manual suggests invoking
* mysql_use_result() and if it succeed the statement is SELECT-like
* that can use a resultSet. Otherwise call mysql_field_count()
* and if it returns zero, the sql was not a SELECT-like statement.
* Finally a non-zero means a failed SELECT-like statement.
*/
my_result = mysql_use_result(my_connection);
if(!my_result)
my_result = (MYSQL_RES *) NULL;
num_fields = (int) mysql_field_count(my_connection);
is_select = (int) TRUE;
if(!my_result){
if(num_fields>0){
free(dyn_statement);
error("error in select/select-like");
}
else
is_select = FALSE;
}
/* we now create the wrapper and copy values */
rsHandle = RS_DBI_allocResultSet(conHandle);
result = RS_DBI_getResultSet(rsHandle);
result->statement = RS_DBI_copyString(dyn_statement);
result->drvResultSet = (void *) my_result;
result->rowCount = (int) 0;
result->isSelect = is_select;
if(!is_select){
result->rowsAffected = (int) mysql_affected_rows(my_connection);
result->completed = 1;
}
else {
result->rowsAffected = (int) -1;
result->completed = 0;
}
if(is_select)
result->fields = RS_MySQL_createDataMappings(rsHandle);
free(dyn_statement);
return rsHandle;
}
