mysql_select_db(3)

💖 mysql_select_db — bestie, let's pick a default database 💖

okay so this is a page from the MariaDB Connector/C manual, and it's about mysql_select_db, the little function that goes "yeah this database? it's the default now, we live here." 🏠✨

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🌸 Name 🌸

mysql_select_db — selects a database as default. that's it, that's the whole job, and she does it flawlessly. 💅

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✨ Synopsis ✨

#include <mysql.h>

int mysql_select_db(MYSQL * mysql,
                    const char * db);

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🦋 Description 🦋

Selects a database as default. Returns zero on success, non-zero on failure — so like, 0 is the slay outcome, anything else means something went sideways, no cap. 😭

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🎀 Parameters 🎀

• mysql — this is a connection identifier, which was previously allocated by mysql_init(3) and connected by mysql_real_connect(3). think of it as your lil connection bestie that has to already exist before you start asking her to switch databases. 🫶
• db — the default database name. literally just the name of the database you want as your new default. 📛

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👑 Notes 👑

• To retrieve the name of the default database, either execute the SQL command SELECT DATABASE() or retrieve the value via the mariadb_get_infov(3) API function. two routes, same destination, pick your fighter. ⭐
• The default database can also be set by the db parameter in mysql_real_connect(3). so if you set it at connect time you're already sorted — this function is for changing it after. 🔥

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🌈 Examples 🌈

💜 SQL

# switch to default database test
USE test;
# check default database
SELECT DATABASE();
+------------+
| database() |
+------------+
| test       |
+------------+

look at that gorgeous little table. the default database is test and everyone clapped. 👏

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🍓 MariaDB Connector/C

static int set_default_db(MYSQL *mysql)
{
  int rc;
  char *default_db;

  /* change default database to test */
  rc= mysql_select_db(mysql, "test");
  if (rc)
    return rc;  /* Error */

  /* get the default database */
  rc= mariadb_get_infov(mysql, MARIADB_CONNECTION_SCHEMA, &default_db);
  if (rc)
    return rc; /* Error */

  if (strcmp("test", default_db) != NULL)
  {
    printf("Wrong default database\n");
    return 1;
  }
  printf("Default database: %s", default_db);
  return 0;
}

so the whole vibe here is: switch the default db, then verify it actually switched, because trust but verify bestie. 🕵️♀️✨

heads up: if the check fails, this prints Wrong default database and returns 1. if everything's cute, it prints Default database: %s and returns 0. 💀 don't skip the error checks, fr fr.

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🧚 See also 🧚

• mysql_real_connect(3)

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and that's the page!! thanks for reading, you're doing amazing sweetie. 💖

this was Version 3.4 of the MariaDB Connector/C manual, page mysql_select_db(3) — mwah, go forth and select your databases. 🎀🦋🌸