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TableData

TableData is the main class used to manipulate a tabale data. You need an object of this class to access a table's data.

You need firstly an object of MemoryManager type

example
MemoryManager mem;

then you can use either TO or FROM methods.

INSERT#

With this methods you can add a new data at the end of a table. Library auto calculates the next position.

Numerics data#

example
template <typename T>TableData& INSERT(char* c_name, const T* data)

  1. c_name: the column name where you want to store the new data

  2. data: a pointer to a numeric data which contains the value to store

example
int new_age = 25;float new_rate = 8.3;
mem.TO("EM")    .INSERT("ag", &new_age)    .INSERT("rt", &new_rate)    .DONE();

In this example, we insert two data new_age and new_rate on the ag and rt of the EM table.

caution
  • data type to store must match column data type set when creating the table
  • if the column doesn't exist (wrong name after took the first 02 chars) no data at this line will not be stored
  • Don't forget to call DONE at the end othwersie the INSERT operation will override the last date in the table and will not update the number of data in the table

Array of char#

If it is an array of char use the specialized version of INSERT function.

prototype
TableData& INSERT(char* c_name, char* data)

  1. c_name: the column name where you want to store the new data

  2. data: the char sequence

example
char hello[] = "Bonsoir";
mem.TO("EM")    .INSERT("nm", hello)    .DONE();

UPDATE#

You can override a data at a position/index. It is like an INSERT operation but you can precise the index you want of data you want to override.

Numerics data#

prototype
template <typename T>TableData& UPDATE(char* c_name, const T* data, int nth)

  1. c_name: the column name where you want to update the new data

  2. data: a pointer to a numeric data which contains the value to store

  3. nth: the index/position where you want to override the data.

example
int new_age = 25;float new_rate = 8.3;
mem.TO("EM")    .UPDATE("ag", &new_age, 2)    .UPDATE("rt", &new_rate, 2)    .DONE();

We override data at position 2 (third data) of the table.

Array of char#

If it is an array of char use the specialized version of UPDATE function.

example
TableData& UPDATE(char* c_name, char* data, int nth)

  1. c_name: the column name where you want to update the new data

  2. data: char array

  3. nth: the index/position where you want to override the data.

example
char hello[] = "Bonsoir";
mem.TO("EM")    .UPDATE("nm", hello, 2)    .DONE();

SELECT#

With this function you can retrieve dat from a table if you konw its name

Numerics data#

prototype
template <typename T>TableData& SELECT(char* c_name, T* data, int nth = 0)

  1. c_name: the column name where you want to read the table data

  2. data: a pointer to the variable that will hold the data read

  3. nth: the index/position where you want to read the data.

  • return an object reference of TableData type that can be used after to do more actions.
example
int age = 0;mem.FROM("EM")    .SELECT("ag", &age)    .DONE();
Serial.print("value read");Serial.println(age);

Array of char#

Use in this case the second version of SELECT function

prototype
TableData& SELECT(char* c_name, char* data, int nth = 0)

  1. c_name: the column name where you want to read the table data

  2. data: char array that will hold the data read

  3. nth: the index/position where you want to read the data.

  • return an object reference of TableData type that can be used after to do more actions.
example
char name[10];
mem.FROM("EM")    .SELECT("nm", name, 0)    .DONE();
Serial.println(name);

SELECT_ALL#

You can select all data directly

Numerics data#

prototype
template <typename T>TableData& SELECT_ALL(char* c_name, T* data, int& nbData)

  1. c_name: the column name where you want to read the table data

  2. data: array that will hold the data read

  3. nbData: an reference to hold the amount of data read

example
int all_age[5];float all_rate[5];int amount = 0;
mem.FROM("EM")    .SELECT_ALL("ag", all_age, amount)    .SELECT_ALL("rt", all_rate, amount)    .DONE();
for (size_t i = 0; i<amount; i++) {    Serial.println(all_age[i]);    Serial.println(all_rate[i]);}

Array of char#

We don't provide yet an implementation of SELECT_ALL for char sequence. But you can write your own wrapper.

WHERE#

Only for numerics data.

You can filter that on what you want to work (get or write) and work so only on data which match some conditions.

prototype
template <typename T>TableData& WHERE(char* c_name, FILTER f, T* data)

  1. c_name: the column name where you want to read the table data

  2. f: A filter enumeration. Read filter doc to know them.

  3. data: data that will be used as comparator

example
int max_age = 25;int all_age[5];int nb = 0;
mem.FROM("EM")    .WHERE("ag", FILTER::isLessThan, &max_age)    .SELECT_ALL("ag", all_age, nb)    .DONE();
for (size_t i = 0; i<nb; i++) {    Serial.println(all_age[i]);}

// or somthing like thisint min_val = 31;float em_rate = 7;
mem.FROM("EM")    .WHERE("ag", FILTER::isGreaterThan, &min_val)    .WHERE("rt", FILTER::isNotEqualTo, &em_rate)    .DELETE(0)    .DONE();

Yes I love this methods and I love chainning functions

info

You can apply after using WHERE the following methods:

  • SELECT
  • SELECT_ALL
  • UPDATE
  • DELETE
  • DELETE_ALL
  • WHERE

DELETE#

You can also delete a data at any position in a table. Remember that trying to delete at a position means delete all data at this position for each columns of the table. If you use a filter fonction (WHERE), delete at index means delete the data which match WHERE filter at this index

prototype
TableData& DELETE(int nth = 0)
  1. nth: the psoition (index) of data
example
mem.TO("EM")    .DELETE(2)    .DONE();

DELETE_ALL#

You can also delete all data at any position in a table. If you use a filter fonction (WHERE), delete all means delete all data which match WHERE filter

prototype
TableData& DELETE_ALL(int& nbData)
  1. nbData: a reference to hold the amount of data deleted
example
int nb = 0;mem.TO("EM")    .DELETE_ALL(nb)    .DONE();
Serial.print("Amount data deleted: "); Serial.println(nb);

DONE#

This method must be called at the end of operations to be sure to keep consistent a table data.

prototype
void DONE()
info

Let's say: TO and FROM functions open a connection to a table of the data base and DONE function close this connection.