sqlite make primary key
# SQLite ->
//if the primary key has only one column,
//you use the PRIMARY KEY column constraint
//to define the primary key as follows:
CREATE TABLE table_name(
column_1 INTEGER NOT NULL PRIMARY KEY,
...
);
// in case primary key consists of two or
//more columns, you use the PRIMARY KEY table
//constraint to define the primary as shown in
//the following statement.
CREATE TABLE table_name(
column_1 INTEGER NOT NULL,
column_2 INTEGER NOT NULL,
...
PRIMARY KEY(column_1,column_2,...)
);