IOS sqlite 基础

1，导入libsqlite3.0.dylib库

文件中：#import"sqlite3.h"

2，创建数据库

#define kDocDir [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]

#define dbPath [kDocDir stringByAppendingPathComponent:@"test.db"]

sqlite3 *db;

if (sqlite3_open([dbPathUTF8String], &db) !=
SQLITE_OK) {

sqlite3_close(db);

NSAssert(0,@"数据库打开失败。");

return;

}

3，创建表table1, 三个不同类型的字段id是整形，name是字符串，image是二进制

char *sqlStr ="CREATE TABLE table1 (id integer, name text, image blob)";

sqlite3_stmt *statement;

if(sqlite3_prepare_v2(db, sqlStr, -1, &statement,nil) !=
SQLITE_OK) {

NSLog(@"Error: failed to prepare statement:create table1");

return;

}

int success = sqlite3_step(statement);

sqlite3_finalize(statement);

if ( success != SQLITE_DONE) {

NSLog(@"Error: failed to dehydrate:CREATE TABLEtable1");

return;

}

4，插入数据，注意问号的个数要和参数匹配

int idvalue=1;

NSString *namevalue=@"value";

UIImage *image=[UIImageimageNamed:@"test.png"];

sqlStr = "INSERT INTO
table1 VALUES(?,?,?)";

int success =
sqlite3_prepare_v2(db, sqlStr, -1, &statement,NULL);

if (success != SQLITE_OK) {

NSLog(@"Error: failed to insert into table1");

}

sqlite3_bind_int(statement,
1, [idvalueintegerValue]);//第二个参数从1开始，与后面查询数据的时候有区别

sqlite3_bind_text(statement,
2, [namevalueUTF8String], -1,SQLITE_TRANSIENT);

sqlite3_bind_blob(statement,
3, [imagebytes], (int)[imagelength],
SQLITE_TRANSIENT);

success = sqlite3_step(statement);

sqlite3_finalize(statement);

if (success == SQLITE_ERROR) {

NSLog(@"Error: failed to insert into the database with message.");

return;

}

5, 查询数据

sqlStr = "SELECT * FROM
table1";

if (sqlite3_prepare_v2(db, sqlStr, -1, &statement,NULL) !=
SQLITE_OK) {

NSLog(@"Error: failed to prepare statement with message:gettable1.");

return;

}

//查询结果集中一条一条的遍历所有的记录，这里的数字对应的是列值。

while (sqlite3_step(statement) ==SQLITE_ROW) {

int tempint=sqlite3_column_int(statement, 0);//这里要从0开始，注意与插入的时候序号的区别

char *temp=(char *)sqlite3_column_text(statement, 1);

NSString *tempstr=temp?[NSString stringWithUTF8String:temp]:@"";

int length=sqlite3_column_bytes(statement,2);//获取到二进制的数据的长度

Byte* bytes=(Byte*)sqlite3_column_blob(statement,2);

NSData *data=[NSDatadataWithBytes:bytes
length:length];

}

6，关闭数据库

sqlite3_close(db);