Linux下SQLite数据库操作:表的检测,创建,删除。
Linux下SQLite数据库操作:表的检测,创建,删除。
- <一> 表的检测,创建,删除。
- #include <stdio.h>
- #include <stdbool.h>
- #include <stdlib.h>
- #include <string.h>
- #include <sqlite3.h>
- bool db_tableExists(sqlite3 *db, const char *tbname)
- {
- int nRet;
- const char *szTail;
- sqlite3_stmt *pvm;
- char sql[1024];
- sprintf(sql, "select count(*) from sqlite_master where type='table' and name='%s'", tbname);
- szTail=0;
- nRet = sqlite3_prepare(db, sql, -1, &pvm, &szTail);
- //printf("nRet=%d SQLITE_OK=%d SQLITE_DONE=%d SQLITE_ROW=%d \n", nRet, SQLITE_OK, SQLITE_DONE,SQLITE_ROW);
- if (nRet==SQLITE_OK)
- {
- nRet=sqlite3_step(pvm);
- //printf("nRet=%d SQLITE_OK=%d SQLITE_DONE=%d SQLITE_ROW=%d \n", nRet, SQLITE_OK, SQLITE_DONE,SQLITE_ROW);
- if (nRet==SQLITE_ROW)
- {
- int nCols = sqlite3_column_count(pvm);
- //printf("nCols:%d\n", nCols);
- if (nCols>=1)
- {
- return sqlite3_column_int(pvm,0)!=0;
- }
- }
- }
- return false;
- }
- int db_exeDML(sqlite3 *db, const char *sql)
- {
- char* szError=0;
- int nRet = sqlite3_exec(db, sql, 0, 0, &szError);
- if (nRet == SQLITE_OK)
- {
- return sqlite3_changes(db);
- }
- return SQLITE_ERROR;
- }
- int main(int argc, char **argv)
- {
- sqlite3 *db=0;
- int nRet = sqlite3_open("temp.db",&db);
- if (nRet)
- {
- fprintf(stderr,"can't open database: %s\n",sqlite3_errmsg(db));
- sqlite3_close(db);
- exit(1);
- }else{
- printf("open database ok.\n");
- }
- if (!db_tableExists(db,"tmp"))
- {
- printf("create \"tmp\" table\n");
- nRet=db_exeDML(db,"CREATE TABLE tmp( IP TEXT, VER TEXT, UID TEXT, FILE TEXT)");
- printf("nRet=%d\n", nRet);
- }else{
- nRet=db_exeDML(db,"delete from tmp");
- printf("nRet=%d\n", nRet);
- }
- sqlite3_close(db);
- return 0;
- }
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