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MemoryManager

MemoryManager is the main class used to access data base. You need an object of this class to work on tables.

TinyDatabase header#

Be sure that the library header was included in your sketch

header
#include <TinyDatabase_Arduino.h>

Work on tables#

Constructor#

constructor
MemoryManager()

To create an object

example
MemoryManager mem;

Erase all#

If it is a new project, be sure to clear all the EEPROM with

prototype
void clearAll()
exemple
mem.clearAll();

Table creation#

You can create easily a table by invoking CREATE_TABLE methods

prototype
int CREATE_TABLE(char* tableName,                 uint8_t capacity,                 uint8_t col,                Column tableCol[])

  1. tableName: the name of your table - no more than 2 char

  2. capacity: the maximum of data that the table can hold. If this value is attended the next data start override old data from the top

  3. col: the number of columns for this table

  4. tableCol: an array of columns structre. Its contain all table's columns with their name and type. Go to Column to know more.

  • return a status code. The creation can be aborted if capacity value exceeds 255 or memory is not available or something else. Check status code to know more.
example
Column allCols[] = {{"ag", "INT"}, {"rt", "FLOAT"}}; mem.CREATE_TABLE("EM", 15, 2, allCols);
  • We create firstly two columns named ag and rt of types INT and FLOAT. Read more about TinyDatabase types
  • Then the table with name EM of 15 as its capacity.
danger

Tables name and columns name cannot be more than 02 characters. Othwersie we cut off and take only the first two char. They follow variables name structure.

tip
  • For table name you can use uppercase letters like EM or PT or underscore as last char like E_ or P_.
  • And use lowercase letter for columns name like ag or hm.

Display meta data#

You can print in Serial monitor informations about the data base: meta data. It contains amount of data, tables informations, address where these informations are stored

prototype
void printMetaData()
example
mem.printMetaData(); // open your serial monitor

Table existence#

You can check if a table exists in the database if you know its name.

prototype
int ON(char* tableName)
  1. tableName: the name of the table you want to check
  • return a negative number (status code) if the table doesn't exist and a positive number if it exists (the address where this tables meta data are stored).

Set data#

There are two mains actions that can be done on a table: write or read. If you want to write or delete data on table:

prototype
TableData& TO(char* tableName)
  1. tableName: the name of table on what you want to work.
  • return a reference to private member of MemoryManager to allow you to chain methods after when setting data on this table. If table doesn't exist, it return an invalid object of TableData.
example
TableData t_data = mem.TO("EM");

Get data#

In the cas where you want to get data from the table:

prototype
TableData& FROM(char* tableName)
  1. tableName: the name of table on what you want to work.
  • return a reference to private member of MemoryManager to allow you to chain methods after when getting data from this table. If table doesn't exist, it returns an invalid object of TableData.
example
TableData t_data = mem.FROM("EM");
tip
  • TO and FROM methods do the samething and has the same structure but it is more readable if you:
  • TO for INSERT, UPDATE, DELETE, DELETE_ALL queries;
  • FROM for SELECT,SELECT_ALL, queries.

Useful methods#

Memory availability#

You can check if there is more memory available in the data base.

prototype
int isMemoryAvailable(int need)
  1. need: the amount of space.
example
int memAvailableStatus =  mem.isMemoryAvailable(100); // open your serial monitor

Data size#

You can check the possible amount data stored in the database (sum of all capacity).

prototype
int size()
example
int amount = mem.size();

Amount of tables#

You can also check the number of tables

prototype
uint8_t nbTables()
caution

You cannot create more than 255 tables in the database.