Sqlite and iossqlite for Ios development

Sqlite and iossqlite for Ios development

Sqlite is an important means of ios data storage. Today, let's take a look at how to use sqlite to store data in the sandbox.

　　Step 1: import a framework libsqlite3.0.dylib

Select TARGETS and click '+' in the Linked Frameworks and Libraries options of General to add

Step 2: Code

1. Find the path in the sandbox

NSArray *path =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);NSString *documentPath = [path objectAtIndex:0]; NSString *dbPath = [documentPath stringByAppendingPathComponent:@"sqlite.db"];

2. Create an sqlite object and perform the open operation.

Sqlite3 * db; // open the database int res = sqlite3_open (dbPath. UTF8String, & db );

3. Create a table

NSString *sql = @"create table if not exists 'student' ('id' integer primary key autoincrement,'studentname' varchar)";int sqlRes = sqlite3_exec(db, sql.UTF8String, NULL, NULL, NULL); if (sqlRes == SQLITE_OK) {     NSLog(@"create table ok"); }

4. insert data into the table

// Add NSString * sql1 = @ "insert into student (studentname) values ('small account')"; int sql1Res = sqlite3_exec (db, sql1.UTF8String, NULL ); if (sql1Res = SQLITE_ OK) {NSLog (@ "insert OK ");}

5. delete data from the table

NSString *deletesql  = @"delete from student where id = 3";int deleres = sqlite3_exec(db, deletesql.UTF8String, NULL, NULL, NULL);if (deleres == SQLITE_OK) {     NSLog(@"delete is ok");}

6. Modify Table Data

// Modify NSString * updateSql = @ "update student set studentname = 'hangling' where id = 4"; int updateres = sqlite3_exec (db, updateSql. UTF8String, NULL); if (updateres = SQLITE_ OK) {NSLog (@ "update is OK ");}

7. query data

Query data and, add, delete, and modify are different. We need to first create a sqlite_stmt object to store the queried data stream (Binary), and then use the sqlite3_prepare_v2 function to prepare, use sqlite3_bind _ to add a query parameter to obtain data, and disable the sqlite_stmt object.

// Query sqlite3_stmt * stmt; NSString * selectSql = @ "select * from student where id =? "; If (sqlite3_prepare_v2 (db, selectSql. UTF8String,-1, & stmt, nil) = SQLITE_ OK) {sqlite3_bind_int (stmt, 1, 4); while (sqlite3_step (stmt) = SQLITE_ROW) {int identity = sqlite3_column_int (stmt, 0); NSLog (@ "% d", identity); char * name = (char *) sqlite3_column_text (stmt, 1 ); NSLog (@ "% @", [NSString stringwithuf8string: name]);} if (stmt) {sqlite3_finalize (stmt );}

8. Disable the sqlite object of the database.

if (db) {        sqlite3_close(db);    }

 

Author: Jerry Education
Source: http://www.cnblogs.com/jerehedu/
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