Question

I want to save the data from USB into the database sqlite3.

Here is data from USB

char T0[8], T1[8], T2[8], T3[8], T4[8];

I create a table with

const char* Temprature_table = "Create table Temprature_1 (ID INTERGER PRIMARY KEY,Thermo_0 decimal(5,1),Thermo_1 decimal(5,1),Thermo_2 decimal(5,1),Thermo_3 decimal(5,1),Thermo_4 decimal(5,1),time DATETIME)";

then I insert data into the table

result = sqlite3_exec (DB,"Insert  into Temprature VALUES(NULL, T0, T1, T2, T3, T4, time)",0,0,&errmsg);

or

char array[256];
sprintf(array, "Insert into Temprature_1 VALUES(NULL, T0, T1, T2, T3, T4, time)");
result = sqlite3_exec (DB,array,0,0,&errmsg);

but there is a problem: “cannot insert data: no such column: T0”.
I do not know why.
Thanks.

Answer 1

You should use prepared statements to bind values to your query. A regular SQL has the form

INSERT INTO Temperature_1 (Thermo_0, Thermo_1) VALUES (23.2, 42.3)

A prepared statement looks like

INSERT INTO Temperature_1 (Thermo_0, Thermo_1) VALUES (?, ?)

which allows for security and performance enhancements. So your final code will look like

sqlite3_stmt *stmt;

sqlite3_prepare_v2(
  db,
  "INSERT INTO Temperature (Thermo_0, Thermo_1) VALUES (?, ?)",
  -1,
  &stmt,
  NULL
);

sqlite3_bind_text(stmt, 1, T0, -1, SQLITE_TRANSIENT);
sqlite3_bind_text(stmt, 2, T1, -1, SQLITE_TRANSIENT);

sqlite3_step(stmt);

See this SQLite introduction to the C API. Your code doesn’t work because you submit the following string to the query engine

INSERT INTO table (T0);

while the syntax of the INSERT statement looks like

INSERT INTO <table> VALUES (<expression>[, <expression>[, ...]])

When the database engine evaluates your query, it can’t know that TO happens to be the name of a variable somewhere in your code, thus issue that error. The SQL is a language of its own, it doesn’t share anything with the C context.

As a final note, the correct spelling seems to be TEMPERATURE, not TEMPRATURE (you missed an E after PR)