Updates

Author: melchisedech333

4 - select all.c

@@ -0,0 +1,55 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <libpq-fe.h>
+#include "settings.h"
+
+int main (int argc, char *argv[])
+{
+    // Connect to the database.
+    PGconn *conn = PQconnectdb("host=" HOSTNAME " dbname=" DATABASE " user=" USERNAME " password=" PASSWORD);
+
+    if (PQstatus(conn) == CONNECTION_BAD) {
+        fprintf(stderr, "Connection to database failed: %s\n", PQerrorMessage(conn));
+        PQfinish(conn);
+        exit(0);
+    }
+
+    printf("Connected!\n");
+
+    PGresult *res = PQexec(conn, "SELECT * FROM example");    
+    
+    if (PQresultStatus(res) != PGRES_TUPLES_OK) {
+        printf("No data retrieved.\n");        
+        PQclear(res);
+        PQfinish(conn);
+        exit(0);
+    }    
+    
+    int ncols = PQnfields(res);
+    int nrows = PQntuples(res);
+
+    printf("Total columns: %d\n",   ncols);    
+    printf("Total rows...: %d\n\n", nrows);    
+
+    // Displays table field names.
+    printf("%s | %s\n", PQfname(res, 0), PQfname(res, 1));
+    printf("---------------------------\n");
+
+    // Retrieve records from the table.
+    for (int a=0; a<nrows; a++) {
+        printf("%s  | %s\n", 
+            PQgetvalue(res, a, 0), 
+            PQgetvalue(res, a, 1));
+    }
+
+    PQclear(res);
+
+    // Close connection.
+    PQfinish(conn);
+    printf("Disconnected!\n");
+
+    return 0;
+}
+
+

5 - delete.c

@@ -0,0 +1,39 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <libpq-fe.h>
+#include "settings.h"
+
+int main (int argc, char *argv[])
+{
+    // Connect to the database.
+    PGconn *conn = PQconnectdb("host=" HOSTNAME " dbname=" DATABASE " user=" USERNAME " password=" PASSWORD);
+
+    if (PQstatus(conn) == CONNECTION_BAD) {
+        fprintf(stderr, "Connection to database failed: %s\n", PQerrorMessage(conn));
+        PQfinish(conn);
+        exit(0);
+    }
+
+    printf("Connected!\n");
+
+    PGresult *res = PQexec(conn, "DELETE FROM example");    
+    
+    if (PQresultStatus(res) != PGRES_COMMAND_OK) {
+        fprintf(stderr, "Delete error, %s\n", PQerrorMessage(conn));    
+        PQclear(res);
+        PQfinish(conn);
+        exit(0);
+    }
+
+    PQclear(res);
+    printf("Records deleted successfully.\n");
+
+    // Close connection.
+    PQfinish(conn);
+    printf("Disconnected!\n");
+
+    return 0;
+}
+
+

readme-pt.md

@@ -87,9 +87,11 @@ De uso geral:
 
 Códigos:
 
-- <b>1 - connect.c</b>: Realiza a conexão com o servidor. 
-- <b>2 - create table.c</b>: Cria e exclui uma tabela no banco de dados. 
-- <b>3 - insert item.c</b>: Insere registros em uma tabela. 
+- <b>1 - connect.c</b>: Realiza a conexão com o servidor.
+- <b>2 - create table.c</b>: Cria e exclui uma tabela no banco de dados.
+- <b>3 - insert item.c</b>: Insere registros em uma tabela.
+- <b>4 - select all.c</b>: Seleciona os registros de uma tabela.
+- <b>5 - delete.c</b>: Exclui registros.
 
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