初入sqlite3 学习汇总（c接口）

介绍       

 SQLite，是一款轻型的数据库，是遵守ACID的关系型数据库管理系统，它包含在一个相对小的C库中。它是D.RichardHipp建立的公有领域项目。它的设计目标是嵌入式的，而且目前已经在很多嵌入式产品中使用了它，它占用资源非常的低，在嵌入式设备中，可能只需要几百K的内存就够了。它能够支持Windows/Linux/Unix等等主流的操作系统，同时能够跟很多程序语言相结合，比如 Tcl、C#、PHP、Java等，还有ODBC接口，同样比起Mysql、PostgreSQL这两款开源的世界著名数据库管理系统来讲，它的处理速度比他们都快。SQLite第一个Alpha版本诞生于2000年5月。 至2015年已经有15个年头，SQLite也迎来了一个版本 SQLite 3已经发布。

安装

windows下去sqlite官网下载下载dll-x86（或dll-x64）和 sqlite-tools两个包，然后解压到某个目录下，再将这个安装目录配置环境变量，如何安装没有问题CMD下输入sqlite3将会显示如下版本信息：

linux下通常会自带安装，如果没有执行sudo apt install sqlite3即可。

常用C接口函数

创建或打开数据库文件

int sqlite3_open(
  const char *filename,   /* Database filename (UTF-8) */
  sqlite3 **ppDb          /* OUT: SQLite db handle */
);
int sqlite3_open16(
  const void *filename,   /* Database filename (UTF-16) */
  sqlite3 **ppDb          /* OUT: SQLite db handle */
);
int sqlite3_open_v2(
  const char *filename,   /* Database filename (UTF-8) */
  sqlite3 **ppDb,         /* OUT: SQLite db handle */
  int flags,              /* Flags */
  const char *zVfs        /* Name of VFS module to use */
);

关闭数据

int sqlite3_close(sqlite3*);
int sqlite3_close_v2(sqlite3*);

执行sql语句

int sqlite3_exec(
  sqlite3*,                                  /* An open database */
  const char *sql,                           /* SQL to be evaluated */
  int (*callback)(void*,int,char**,char**),  /* Callback function */
  void *,                                    /* 1st argument to callback */
  char **errmsg                              /* Error msg written here */
);

exec其实是封装了下面三个函数

语句对象

typedef struct sqlite3_stmt sqlite3_stmt;

int sqlite3_prepare(//准备语句对象
  sqlite3 *db,            /* Database handle */
  const char *zSql,       /* SQL statement, UTF-8 encoded */
  int nByte,              /* Maximum length of zSql in bytes. */
  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
);
int sqlite3_prepare_v2(
  sqlite3 *db,            /* Database handle */
  const char *zSql,       /* SQL statement, UTF-8 encoded */
  int nByte,              /* Maximum length of zSql in bytes. */
  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
);
int sqlite3_prepare_v3(
  sqlite3 *db,            /* Database handle */
  const char *zSql,       /* SQL statement, UTF-8 encoded */
  int nByte,              /* Maximum length of zSql in bytes. */
  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
);

int sqlite3_step(sqlite3_stmt*);//执行语句

int sqlite3_finalize(sqlite3_stmt *pStmt);//销毁语句

获得绑定的索引个数

int sqlite3_bind_parameter_count(sqlite3_stmt*);通过名称获得项的索引号

int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);

通过名称获得项的索引号

int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);

通过索引项获得名称

const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);

为语句对象增加数据

int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
                        void(*)(void*));
int sqlite3_bind_double(sqlite3_stmt*, int, double);
int sqlite3_bind_int(sqlite3_stmt*, int, int);
int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
int sqlite3_bind_null(sqlite3_stmt*, int);
int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
                         void(*)(void*), unsigned char encoding);
int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);

重置语句对象，重新绑定

int sqlite3_reset(sqlite3_stmt *pStmt);

返回查询结果集的某一列

const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
double sqlite3_column_double(sqlite3_stmt*, int iCol);
int sqlite3_column_int(sqlite3_stmt*, int iCol);
sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
int sqlite3_column_type(sqlite3_stmt*, int iCol); 

查询获取结果

int sqlite3_get_table(
  sqlite3 *db,          /* An open database */
  const char *zSql,     /* SQL to be evaluated */
  char ***pazResult,    /* Results of the query */
  int *pnRow,           /* Number of result rows written here */
  int *pnColumn,        /* Number of result columns written here */
  char **pzErrmsg       /* Error msg written here */
);
void sqlite3_free_table(char **result); //不要直接用sqlite3_free函数释放

分配和释放内存

void *sqlite3_malloc(int);
void *sqlite3_malloc64(sqlite3_uint64);
void *sqlite3_realloc(void*, int);
void *sqlite3_realloc64(void*, sqlite3_uint64);
void sqlite3_free(void*);
sqlite3_uint64 sqlite3_msize(void*);

执行错误码#define SQLITE_OK           0   /* Successful result */
#define SQLITE_ERROR        1   /* SQL error or missing database */
#define SQLITE_INTERNAL     2   /* An internal logic error in SQLite */
#define SQLITE_PERM         3   /* Access permission denied */
#define SQLITE_ABORT        4   /* Callback routine requested an abort */
#define SQLITE_BUSY         5   /* The database file is locked */
#define SQLITE_LOCKED       6   /* A table in the database is locked */
#define SQLITE_NOMEM        7   /* A malloc() failed */
#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite_interrupt() */
#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
#define SQLITE_NOTFOUND    12   /* (Internal Only) Table or record not found */
#define SQLITE_FULL        13   /* Insertion failed because database is full */
#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
#define SQLITE_EMPTY       16   /* (Internal Only) Database table is empty */
#define SQLITE_SCHEMA      17   /* The database schema changed */
#define SQLITE_TOOBIG      18   /* Too much data for one row of a table */
#define SQLITE_CONSTRAINT  19   /* Abort due to contraint violation */
#define SQLITE_MISMATCH    20   /* Data type mismatch */
#define SQLITE_MISUSE      21   /* Library used incorrectly */
#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
#define SQLITE_AUTH        23   /* Authorization denied */
#define SQLITE_ROW         100  /* sqlite_step() has another row ready */
#define SQLITE_DONE        101  /* sqlite_step() has finished executing */

案例

#include
#include
#include

/***************************
typedef int (*sqlite3_callback)(
void*,    // Data provided in the 4th argument of sqlite3_exec()
int,        // The number of columns in row
char**,   // An array of strings representing fields in the row
char**    // An array of strings representing column names
);

***************************/

/* callback函数只有在对数据库进行select, 操作时才会调用 */
static int select_callback(void *data, int argc, char **argv, char **azColName){
   int i;
   printf("%s", (char*)data);
   for(i=0; i < argc; i++){
      printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
   }
   printf("\n");
   return 0;
}

int main(int argc, char* argv[])
{
   sqlite3 *db;
   char *zErrMsg = 0;
   int rc;

   /* 数据库创建或打开 */
   rc = sqlite3_open("test.db", &db);

   if( rc ){
      fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));
      exit(0);
   }else{
      fprintf(stderr, "Opened database successfully\n");
   }

   char* sql;
   sql = "create table healthinfo (" \
           "sid int primary key not null," \
           "name text not null," \
           "ishealth char(4) not null);";

   /* 创建表 */
   rc = sqlite3_exec(db, sql, NULL, NULL, &zErrMsg);
   if( rc != SQLITE_OK ){
      fprintf(stderr, "SQL error: %s\n", zErrMsg);
      sqlite3_free(zErrMsg);
   }else{
      fprintf(stdout, "Table created successfully\n");
   }

   sql = "insert into healthinfo (sid, name, ishealth)" \
           "values (201601001, 'xiaowang', 'yes');" \
           "insert into healthinfo (sid, name, ishealth)" \
           "values (201601002, 'xiaoli', 'yes');" \
           "insert into healthinfo (sid, name, ishealth)" \
           "values (201601003, 'xiaozhang', 'no');" \
           "insert into healthinfo (sid, name, ishealth)" \
           "values (201601004, 'xiaozhou', 'yes');" \
           "insert into healthinfo (sid, name, ishealth)" \
           "values (201601005, 'xiaosun', 'yes');";

    /* 插入数据 */
   rc = sqlite3_exec(db, sql, NULL, NULL, &zErrMsg);
   if( rc != SQLITE_OK ){
      fprintf(stderr, "SQL error: %s\n", zErrMsg);
      sqlite3_free(zErrMsg);
   }else{
      fprintf(stdout, "Table insert data successfully\n");
   }

   char* strname = "xiaoyang";
   //char strname[256] = {'x','i','a','o','y','a','n','g'};
   char sql2[256] = {'0'};
   /* 不推荐使用这种方式 */
   sprintf(sql2, "insert into healthinfo (sid, name, ishealth) values (201601006, '%s', 'yes');", strname);
    /* 插入数据 */
   rc = sqlite3_exec(db, sql2, NULL, NULL, &zErrMsg);
   if( rc != SQLITE_OK ){
      fprintf(stderr, "SQL error: %s\n", zErrMsg);
      sqlite3_free(zErrMsg);
   }else{
      fprintf(stdout, "Table insert data successfully\n");
   }

   /***********  存数据和取数据的第二种方法***********/

   sql = "insert into healthinfo (sid, name, ishealth)" \
           "values (:sid, :name, :ishealth);";   /* 注: ":sid" 为命名参数 也可以用? 号*/

   sqlite3_stmt *stmt;
   /* 准备一个语句对象 */
   sqlite3_prepare_v2(db, sql, strlen(sql), &stmt, NULL);
   /* 语句对象绑定的参数个数也就是上面sql语句values括号中的参数 */
   printf("max_parameter_count = %d\n", sqlite3_bind_parameter_count(stmt));
   /* 只有上面指定了:sid这个名字才可以用 */
   printf("sid parameter index = %d\n", sqlite3_bind_parameter_index(stmt, ":sid"));
   printf("name parameter index = %d\n", sqlite3_bind_parameter_index(stmt, ":name"));
   printf("ishealth parameter index = %d\n", sqlite3_bind_parameter_index(stmt, ":ishealth"));
   /* 如果是?号命名的则返回的文本为null */
   printf("index = 1 's parameter's name = %s\n", sqlite3_bind_parameter_name(stmt, 1));
   sqlite3_bind_int(stmt, 1, 201601007);
   sqlite3_bind_text(stmt, 2, "xiaoqian", -1, NULL); /* 第四个参数设为负数则自动计算第三个参数的长度 */
   sqlite3_bind_text(stmt, 3, "yes", 3, NULL);
   //sqlite3_bind_blob(stmt, 1, sectionData, 4096, SQLITE_STATIC); /* 将sectonData 绑定到stmt对象 */

   /* 执行sql 语句对象并判断其返回值
       发现如果不是select 这样会产生结果集的操作
       返回值为SQLITE_DONE 或者出错，只有执行sql语句会产生
       结果集执行step函数才返回SQLITE_ROW*/
   rc = sqlite3_step(stmt);
   printf("step() return %s\n", rc == SQLITE_DONE ? "SQLITE_DONE" \
                                          : rc == SQLITE_ROW ? "SQLITE_ROW" : "SQLITE_ERROR");

    sqlite3_reset(stmt);  /* 如果要重新绑定其他值要reset一下 */
    sqlite3_bind_int(stmt, 1, 201601008);
    sqlite3_bind_text(stmt, 2, "xiaowu", -1, NULL); /* 重新绑定值 */
    sqlite3_bind_text(stmt, 3, "yes", 3, NULL);
    sqlite3_step(stmt);  /* 再执行 */

   /* 销毁prepare 创建的语句对象 */
   sqlite3_finalize(stmt);

   /* 取数据 */
   //sql = "select * from healthinfo;";
   sql = "select * from healthinfo limit 4 offset 2;";  /* 限制返回4行且从第3行开始 */
   sqlite3_prepare_v2(db, sql, strlen(sql), &stmt, NULL);
   printf("total_column = %d\n", sqlite3_column_count(stmt));

   /* 遍历执行sql语句后的结果集的每一行数据 */
   while(sqlite3_step(stmt) == SQLITE_ROW){
       /* 获得字节数，第二个参数为select结果集合的列号 */
       /* 由于select 的结果集只有section这一列，因此为0 */
       int len_sid = sqlite3_column_bytes(stmt, 0);
       int len_name = sqlite3_column_bytes(stmt, 1);
       int len_ishealth = sqlite3_column_bytes(stmt, 2);

       printf("sid = %d, len = %d\n", sqlite3_column_int(stmt, 0), len_sid);
       printf("name = %s, len = %d\n", sqlite3_column_text(stmt, 1), len_name);
       printf("ishealth = %s, len = %d\n", sqlite3_column_text(stmt, 2), len_ishealth);
       //unsigned char* srcdata = sqlite3_column_blob(stmt, 0);  /* 取得数据库中的blob数据 */
   }
   printf("\n");
   sqlite3_finalize(stmt);
   /******************* end ****************************/


   const char* data = "select call back function call!\n";
   /* select 使用*/
   sql = "select * from healthinfo where ishealth == 'yes';";
   rc = sqlite3_exec(db, sql, select_callback, data, &zErrMsg);
   if( rc != SQLITE_OK ){
      fprintf(stderr, "SQL error: %s\n", zErrMsg);
      sqlite3_free(zErrMsg);
   }else{
      fprintf(stdout, "Table select successfully\n");
   }

   data = "update call back function call!\n";
   /* update 使用*/
   sql = "update healthinfo set ishealth = 'no' where name='xiaoli';" \
            "select * from healthinfo where ishealth == 'yes';";
   rc = sqlite3_exec(db, sql, select_callback, data, &zErrMsg);
   if( rc != SQLITE_OK ){
      fprintf(stderr, "SQL error: %s\n", zErrMsg);
      sqlite3_free(zErrMsg);
   }else{
      fprintf(stdout, "Table update successfully\n");
   }


   /* 删除表 */
   sql = "drop table healthinfo;";
   rc = sqlite3_exec(db, sql, NULL, NULL, &zErrMsg);
   if( rc != SQLITE_OK ){
      fprintf(stderr, "SQL error: %s\n", zErrMsg);
      sqlite3_free(zErrMsg);
   }else{
      fprintf(stdout, "Table droped successfully\n");
   }


   char sql5[256];
   char* tname = "abc";
   sprintf(sql5, "create table if not exists %s ("\
                    "id int not null," \
                    "name text not null);", tname);

   printf("%s\n", sql5);

   /* 创建表 */
   rc = sqlite3_exec(db, sql5, NULL, NULL, &zErrMsg);
   if( rc != SQLITE_OK ){
      fprintf(stderr, "SQL error: %s\n", zErrMsg);
      sqlite3_free(zErrMsg);
   }else{
      fprintf(stdout, "Table created successfully\n");
   }

   sqlite3_close(db);
}