Add Small Db example

Author: siara-cc

examples/sqlite3_small_db/sqlite3_small_db.ino

@@ -0,0 +1,96 @@
+/*
+    This example opens Sqlite3 databases from SD Card and
+    retrieves data from them.
+    Before running please copy following files to SD Card:
+    data/babyname.db
+
+    Also increase stack size in cores/esp8266/cont.h
+    to atleast 6144 (from 4096).
+
+    Please see https://github.com/siara-cc/esp_arduino_sqlite3_lib/
+    for more information.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sqlite3.h>
+#include <vfs.h>
+#include <SPI.h>
+extern "C" {
+#include "user_interface.h"
+}
+#include <ESP8266WiFi.h>
+
+void WiFiOff() {
+    wifi_station_disconnect();
+    wifi_set_opmode(NULL_MODE);
+    wifi_set_sleep_type(MODEM_SLEEP_T);
+    wifi_fpm_open();
+    wifi_fpm_do_sleep(0xFFFFFFF);
+}
+
+int openDb(const char *filename, sqlite3 **db) {
+  int rc = sqlite3_open(filename, db);
+  if (rc) {
+      Serial.printf("Can't open database: %s\n", sqlite3_errmsg(*db));
+      return rc;
+  } else {
+      Serial.printf("Opened database successfully\n");
+  }
+  return rc;
+}
+
+void setup ( void ) {
+
+    sqlite3 *db1;
+    int rc;
+    sqlite3_stmt *res;
+    int rec_count = 0;
+    const char *tail;
+
+    Serial.begin(74880);
+
+    system_update_cpu_freq(SYS_CPU_160MHZ);
+    WiFiOff();
+
+    SPI.begin();
+    vfs_mount("/SD0", SS);
+
+    sqlite3_initialize();
+
+    // Open database 1
+    if (openDb("/SD0/babyname.db", &db1))
+        return;
+
+    String sql = "Select year, state, name, total_babies, primary_sex, primary_sex_ratio, \
+                    per_100k_in_state from gendered_names \
+                    where name between 'Bob' and 'Bobby'";
+    rc = sqlite3_prepare_v2(db1, sql.c_str(), 1000, &res, &tail);
+    if (rc != SQLITE_OK) {
+        String resp = "Failed to fetch data: ";
+        resp += sqlite3_errmsg(db1);
+        resp += "<br><br><a href='/'>back</a>";
+        Serial.println(resp.c_str());
+        return;
+    }
+
+    while (sqlite3_step(res) == SQLITE_ROW) {
+        Serial.printf("Year: %d\n", sqlite3_column_int(res, 0));
+        Serial.printf("State: %s\n", (const char *) sqlite3_column_text(res, 1));
+        Serial.printf("Name: %s\n", (const char *) sqlite3_column_text(res, 2));
+        Serial.printf("Total babies: %d\n", sqlite3_column_int(res, 3));
+        Serial.printf("Primary sex: %s\n", (const char *) sqlite3_column_text(res, 4));
+        Serial.printf("Ratio: %lf\n", sqlite3_column_double(res, 5));
+        Serial.printf("Per 100k in state: %lf\n\n", sqlite3_column_double(res, 6));
+        rec_count++;
+    }
+    Serial.printf("No. of records: %d", rec_count);
+
+    sqlite3_finalize(res);
+
+    sqlite3_close(db1);
+
+}
+
+void loop () {
+}