C language Use SQLITE3 database "section III"

int sqlite3_get_table (  sqlite3 *db,/          * Database handle */  const char *zsql,/     * SQL statement */  Char ***pazresult,
     /* query results A large array of one-dimensional arrays *  /int *pnrow,/           * Number of rows */  int *pncolumn,/        * Number of fields that's how many columns but the data is also based on this. For example: First line: 1 , 2,3 then this value defaults to 3, because the first row is the field name, the natural is the number of columns, then how to take the individual data bit?                           A: Starting from the next line for example, 4 is the first data, and then the left-to-right movement, the value changes, the formation of data positioning! Personal understanding, the great God do not spray! *  /char **pzerrmsg/       * error message same as previous errmsg */); sqlite3_free_table (char **result);//release cache of queries

Then please look at the following source code comments:

# include <stdio.h> # include "Sqlite3.h" # include <stdlib.h> int main (void) { int i; Int J; Sqlite3 *db;//establishes a sqlite3 type of pointer db! can act as a handle to the database. Without this handle, all sqlite3 functions have no real meaning. const char *sql1= "INSERT into SJK values (1, ' myd ', ' 2013-10-9 ');"; /assign a SQL statement to a variable! const char *sql2= "INSERT into SJK values (2, ' myd ', ' 2013-10-9 ');"; /sql statement I will not say more. Querying data from a database const char *sql3= "SELECT * from SJK;"; /Here is the point where we can see the use of the callback function at the bottom! Char *errmsg=0; char** PResult; int nrow; int ncol; int Feedback = Sqlite3_open ("sqlite3.db", &db); Opens the specified database file if it does not exist, creates a database file with the same name, and returns the value to the DB handle. if (Feedback! = SQLITE_OK) { printf ("The database named: sqlite3.db is not open \ nthe reason is:%s\n", sqlite3_errmsg (db)); System ("pause"); Sqlite3_errmsg () is the prompt message after returning an error! The parameter is the operation handle of the database. Sqlite3_close (DB); Sqlite3_close () is the database that closes the specified database handle! Exit (-1);//non-normal exit! } else printf ("successfully opened or successfully created named: Sqlite3.db!\n"); Sqlite3_exec (DB, "CREATE TABLE SJK (ID integer,name text,birthday blob)", 0,0,&errmsg);//CREATE TABLE Sqlite3_exec (db,sql1,0,0,&errmsg);//Insert Data 1 Sqlite3_exec (db,sql2,0,0,&errmsg);//Insert Data 2 printf ("Insert data successfully \ n"); Feedback = sqlite3_get_table (db,sql3,&presult,&nrow,&ncol,&errmsg);//query data returns data to &presult int nIndex = Ncol; I did comment parsing before this article started, check it out, and then analyze why? printf ("Total%d columns/n", nIndex);//Find out the default number of fields equals the number of columns for (i=0;i<nrow;i++)//Query the first few lines of the loop { for (j=0;j<ncol;j++)//Query The data loop inside a row { printf ("%s=%s\n", Presult[j],presult[nindex]); ++nindex;//Locate the next data so that the field name matches! } } Sqlite3_free_table (PResult);//Release memory Sqlite3_close (db);//Close Database db = 0;//Clear database handle printf ("Database shutdown succeeded!") \ n "); System ("pause");//Pause dos for easy viewing return 0; }

Then the basics of this tutorial will be here!
However, some people ask me, why do I always use source code and comments to explain it to you from the second class?
Nor is it exaggerated, I ask you, if you do not learn SQL statements will also consider which platform SQLite applies to?
If you do not have C language, then you will also use C language to manipulate SQLite? So many basic questions I will not explain to you.
So the next chapter, I will explain the intermediate article for you. To use it to do some DOS word game!

C language Use SQLITE3 database "section III"