Ios-sqlite3 database: Create TABLE database tables and additions and deletions to database tables (Create/insert/delete)

Source: Internet
Author: User

1. The steps are:

First join the SQLite development Library Libsqlite3.dylib,

Create a new or open database,

Create a data table,

Insert Data,

Querying data and printing

2, the method of SQLite

Sqlite3 *db, database handle, similar to file handle files

Sqlite3_stmt *stmt, an ODBC-equivalent command object that holds compiled SQL statements

Sqlite3_open (), open the database when it is created without a database.
Sqlite3_exec (), execute non-query SQL statement
Sqlite3_step (), use this function to move through the recordset after calling Sqlite3_prepare.
Sqlite3_close (), close the database file
There is also a series of functions that are used to fetch data from a recordset field, such as
Sqlite3_column_text (), take the text type of data.
Sqlite3_column_blob (), fetching blob-type data
Sqlite3_column_int (), take int type of data

3. Operation of database tables: Create and Update/insert/delete/select

Creating a database table (CREATE TABLE)

+ (BOOL) createtable {

Determine if the database is open

if ([sharedatabase Open]) {

If the table Inner_ac_info does not exist, it is created, contains the field column name _id (data type is integer, primary key, auto increment), ac_name (data type varchar), iu_no (data type varchar), ou_ No (data type varchar), GW_IP (data type varchar).

nsstring *sql = @ "CREATE TABLE IF not EXISTS inner_ac_info (_id Integer primary key autoincrement, Ac_name Varcha R, Iu_no varchar, ou_no varchar, gw_ip varchar) ";

[sharedatabase executeupdate:sql];

nsstring *sql1 = @ "CREATE TABLE IF not EXISTS ac_mode_info (_id Integer primary key autoincrement, Ac_mode_name V Archar, On_off Integer, Speed Integer, work_mode integer, temp integer) ";

[sharedatabase EXECUTEUPDATE:SQL1];

nsstring *sql2 = @ "CREATE TABLE IF not EXISTS ac_mode_inner_ac (_id Integer primary key AutoIncrement, ac_mode_id Long, ac_id long) ";

[sharedatabase executeupdate:sql2];        

[Sharedatabase Close];

}

SQLite's autoincrement is a keyword that is used to automatically increment the value of a field in a table.

The keyword autoincrement can only be used for integer fields.

/**

Querying database tables

+ (Nsarray *) getaclist{

Nsmutablearray *acarray = [[Nsmutablearray alloc] init];

[self init];

if ([sharedatabase Open]) {

Query database table The following sentence

fmresultset *s = [sharedatabase executeQuery: [nsstring stringwithformat: @ " SELECT * from Inner_ac_info "]];

< span class= "s2" >         //equivalent to  nsstring *string = [nsstring < Span class= "S3" >stringwithformat:@ "select * from Inner_ac_info" ]&NBSP;

+ fmresultset *s = [sharedatabase executeQuery: string];

While ([s next]) {

airconditioner *ac = [[airconditioner alloc] init];

AC.acId = [nsnumber numberwithint:[s intforcolumn:@ "_id"];

AC.rmname = [s stringforcolumn:@ "Ac_name"];

AC.Aciuno = [s stringforcolumn:@ "Iu_no"];

AC.Acouno = [s stringforcolumn:@ "Ou_no"];

AC.GWIP = [s stringforcolumn:@ "Gw_ip"];

[Acarray Addobject:ac];

}

Close the database

[sharedatabase Close];

}

return acarray;

}

Updating database table Modifications (update)

+ (void) Updateac: (airconditioner*) ac{

[self init];

NSLog(@ "Acid =========%@", AC.acid);

if ([sharedatabase Open]) {

Database tables Perform update operations: Modify the nkname of the ID corresponding

[Sharedatabase executeupdate:

@ "UPDATE inner_ac_info set ac_name =?" where _id =? " , AC.nkname, AC.acId];

[Sharedatabase close];

}

}

Delete a database table

Delete part

+ (void) Deleteac: (nsstring*) Iuno with: (nsstring*) ouno{

[self init];

if ([sharedatabase Open]) {

[Sharedatabase executeupdate:

@ "Delete from inner_ac_info where iu_no =?" and Ou_no =? " , Iuno, Ouno];

[Sharedatabase close];

}

}

Delete all

+ (void) deleteallac{

[self init];

if ([sharedatabase Open]) {

[Sharedatabase executeupdate:

@ "Delete from Inner_ac_info"];

[Sharedatabase close];

}

}

Ios-sqlite3 database: Create TABLE database tables and additions and deletions to database tables (Create/insert/delete)

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.