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//-----------------------------------------------------------------------------
// Copyright (c) 2020, 2022, Oracle and/or its affiliates.
//
// This software is dual-licensed to you under the Universal Permissive License
// (UPL) 1.0 as shown at https://oss.oracle.com/licenses/upl and Apache License
// 2.0 as shown at http://www.apache.org/licenses/LICENSE-2.0. You may choose
// either license.
//
// If you elect to accept the software under the Apache License, Version 2.0,
// the following applies:
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// DemoFetchJSON.c
// Demos fetching JSON values from the database. This requires Oracle Client
// and Oracle Database to both be 20 or higher.
//-----------------------------------------------------------------------------
#include "SampleLib.h"
#define SQL "select" \
" json_array(" \
" json_scalar(1)," \
" json_scalar('String value')," \
" json_object(" \
" key 'Fred' value json_scalar(5)," \
" key 'George' value json_scalar('A string')" \
" returning json)," \
" json_array(" \
" json_scalar(utl_raw.cast_to_raw('A raw'))," \
" json_scalar(sysdate - 1)," \
" json_scalar(systimestamp + 1)" \
" returning json)" \
" returning json) " \
"from dual"
//-----------------------------------------------------------------------------
// displayJson()
//-----------------------------------------------------------------------------
void displayJson(dpiJsonNode *node, uint32_t indentLevel, int printIndent)
{
dpiTimestamp *timestamp;
dpiJsonArray *array;
dpiJsonObject *obj;
uint32_t i, j;
if (printIndent) {
printf("\n");
for (i = 0; i < indentLevel; i++)
printf(" ");
}
switch (node->nativeTypeNum) {
case DPI_NATIVE_TYPE_DOUBLE:
printf("%g", node->value->asDouble);
break;
case DPI_NATIVE_TYPE_BYTES:
printf("'%.*s'", node->value->asBytes.length,
node->value->asBytes.ptr);
break;
case DPI_NATIVE_TYPE_TIMESTAMP:
timestamp = &node->value->asTimestamp;
printf("%.4d-%.2d-%.2d %.2d:%.2d:%.2d", timestamp->year,
timestamp->month, timestamp->day, timestamp->hour,
timestamp->minute, timestamp->second);
break;
case DPI_NATIVE_TYPE_JSON_ARRAY:
array = &node->value->asJsonArray;
printf("[");
for (i = 0; i < array->numElements; i++) {
if (i > 0)
printf(",");
displayJson(&array->elements[i], indentLevel + 1, 1);
}
printf("\n");
for (i = 0; i < indentLevel; i++)
printf(" ");
printf("]");
break;
case DPI_NATIVE_TYPE_JSON_OBJECT:
obj = &node->value->asJsonObject;
printf("{");
for (i = 0; i < obj->numFields; i++) {
if (i > 0)
printf(",");
printf("\n");
for (j = 0; j < indentLevel + 1; j++)
printf(" ");
printf("'%.*s': ", obj->fieldNameLengths[i],
obj->fieldNames[i]);
displayJson(&obj->fields[i], indentLevel + 1, 0);
}
printf("\n");
for (i = 0; i < indentLevel; i++)
printf(" ");
printf("}");
break;
default:
printf("Unhandled native type %u", node->nativeTypeNum);
}
}
//-----------------------------------------------------------------------------
// main()
//-----------------------------------------------------------------------------
int main(int argc, char **argv)
{
dpiNativeTypeNum nativeTypeNum;
uint32_t bufferRowIndex;
dpiData *jsonColValue;
dpiJsonNode *topNode;
dpiConn *conn;
dpiStmt *stmt;
int found;
// connect to database
conn = dpiSamples_getConn(0, NULL);
// perform query
if (dpiConn_prepareStmt(conn, 0, SQL, strlen(SQL), NULL, 0, &stmt) < 0)
return dpiSamples_showError();
if (dpiStmt_execute(stmt, DPI_MODE_EXEC_DEFAULT, NULL) < 0)
return dpiSamples_showError();
// fetch row
if (dpiStmt_fetch(stmt, &found, &bufferRowIndex) < 0)
return dpiSamples_showError();
if (dpiStmt_getQueryValue(stmt, 1, &nativeTypeNum, &jsonColValue) < 0)
return dpiSamples_showError();
if (dpiJson_getValue(jsonColValue->value.asJson, DPI_JSON_OPT_DEFAULT,
&topNode) < 0)
return dpiSamples_showError();
// display results
printf("JSON value:\n");
displayJson(topNode, 0, 0);
printf("\n");
return 0;
}
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