realm database ios

How do I match JSON data to database data when I'm working on an iOS interface with multiple JSON strings coming in from the other side? My idea is to determine how many JSON strings there are based on the JSON array that came from iOS, and then loop the match. I do not know whether the method is correct. How do I tell how many JSON strings are in a JSON arra

]]; if(!result) {NSLog (@"operation failed "%d" = = sql:%@", I,arraysql[i]); } } } @catch(NSException *exception) {Isrollback=YES; ///rolling back[_tydatabase rollback]; } @finally { if(!isrollback) { ///Submit[_tydatabase commit]; }} [_tydatabase close];}Multi-threaded transactions/** Multi-threaded Transaction arraysql:sql statement array*/+ (void) Begintransactiont: (Nsarray *) arraysql{Fmdatabasequeue*databasequeue =[Fmdatabasequeue databasequeuewithpath:[se

resulting value will be the converted result. 4. The type int sqlite3_column_type (sqlite3_stmt*, int icol) that gets the data for a column in the data row; The return value: Sqlite_integer,sqlite_float,sqlite_text, Sqlite_blob,sqlite_null uses a method similar to the SQLITE3_COLUMN_XXX () function. There are many application programs on the Mac that can be used to produce it, and the UI interface is convenient. However, if you do not want to install the software separately, the MAC system also

SQLite is to support multi-threaded operation, the need to initialize the database is to do a thread-safe config, refer to the following links, looks more complex.Http://www.cnblogs.com/wfwenchao/p/3964213.htmlMany iOS projects use Fmdb, a third-party open Source Library, but Fmdb cannot co-fmdatabase objects in multiple threads, because the class itself is not thread-safe, and if such use causes problems s

dataif (erromsg) {//If there is an errorNSLog (@ "Insert data failed--%s", erromsg);} else {NSLog (@ "Insert data successfully");}}Delete the data and insert the data, just replace the SQL statement.Query data:const char *sql = "SELECT ID, Name, age from T_student WHERE age Preparation before querying-1 means the system automatically calculates the length of the SQL statementSQLITE3_STMT: Used to fetch datasqlite3_stmt *stmt = NULL;if (SQLITE3_PREPARE_V2 (self.db, SQL,-1, stmt, NULL) = = SQLITE

you do not need to pass the pointer to the callback function, you can fill null. Let's see how the callback function is written, and how this parameter is used.The 5th parameter is an error message.SQLITE3_PREPARE_V2 (sqlite3 *db, const char *zsql, int nbyte, sqlite3_stmt **ppstmt, const char **pztail)int nByte-1 means that the length of the SQL statement can be infinitely longSQLITE3_STMT Follow the pointer addressconst CHAR **pztail Intercept SQL statement not used partiallyBinding query valu

Ios database sqlite-third-party framework FMDB, thread-safe transaction processing, sqlite-fmdb Import sqlite3 database and third-party framework FMDB // 1. Obtain the sandbox path NSString * path = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) firstObject]; Path = [path stringByAppendingPathComponent: @ "FMDB. sqlite"]; NSLog

If the IOS App uses CoreData and has database updates (new tables, fields, and other operations) in the previous version, it is necessary to migrate the CoreData database when overwriting the installation program, the procedure is as follows: 1. Select Your mydata. xcdatamodeld file and choose editor> Add Model Version from the menu, for example, mydata2.xcdatamo

Usually, when you clear the table, you also need to reset the self-increment column to zero. Here's how to define a self-increment column in SQLite: 1 CREATE TABLE TableName (id INTEGER PRIMARY KEY autoincrement, ...); A table named Sqlite_sequence is automatically created when the SQLite database contains a self-increment column. This table consists of two columns: name and seq. The name records the table where the inc

First, the use of code to bulk Add (import) data into the database1. Execute SQL statement to add a message to the databaseSQL statement that inserts a single piece of data:　　After clicking Run to execute the statement, refresh the data2. Use code to bulk add multi-line data samples in iOS projectscode example:1 //2 //main.m3 //01-Add multiple rows of data to the database4 //5 //Created by Apple on 14-7-26.6 //Copyright (c) 2014 wendingding. All right

iOS database SQLite and the use of Meassqlite software 1. Introduction to the DatabaseRequirements: Use a database to maintain a high volume of complex data when you need to keep a traffic testCommon Database(1) Microsoft SQL Server 2000/2008 is a relational database managem

How to Create a CocoaPods public database for iOS, ioscocoapodsIntroduction In the development process, the third framework is often used.pod installCommand to easily add a third-party framework to our own project. If we want to open source components or libraries that we write, so that others canpod installHow can I install my own framework using commands? Next, I will teach you how to add your ownpodsPubl

a foreign key called fk_t_student_class_id_t_class_id in the T_student table.The role of this foreign key is to refer to the ID field of the T_class table using the class_id field in the T_student table4. Table Connection QueryTable Join query: You need to federate multiple tables to find the data you wantTypes of table joinsInner joins: INNER JOIN or join (displays records with a full field value in the left and right tables)Left outer connection: Left OUTER join (guarantees the integrity of d

(stmt,1, [data bytes], [data length],Nil);if(Sqlite3_step (stmt) = = Sqlite_done) {NSLog(@"Add Success"); }return YES; }NSLog(@"%@ failed", SQLSTR);return NO;Read data (read from database):Sqlite3 *db = [db OpenDatabase]; Sqlite3_stmt *stmt =Nil;NSString*SQLSTR = [NSStringstringwithformat:@"SELECT * from Hjl_list"];intresult = Sqlite3_prepare (db, [Sqlstr utf8string],-1, stmt,Nil);if(Result = = SQLITE_OK) { while(Sqlite3_step (stmt) = = Sqlite_row)

the query before checking that the SQL statement is correct.*sqlite3_step (stmt) extracts the data from the query and extracts one at a time.//through loops, all data can be retrieved*sqlite3_column_text (stmt, 0) takes out the data in column No. 0. 6. Close the database Sqlite3_close (Sqlite3 *);————————————————————————————————————————————————————————————————————————————————————————————————————————execute an SQL statement with parametersNSString *sq

/** Determine if a table already exists @param tablename table name*/-(BOOL) isexisttable: (NSString *) tablename{if([_database Open]) {Fmresultset*rs = [_database executeQuery:@"Select COUNT (*) as ' count ' from sqlite_master where type = ' table ' and name =?", TableName]; while([Rs next]) {Nsinteger count= [Rs Intforcolumn:@"Count"]; if(0==count) { returnNO; } Else{ returnYES; } } returnNO; } returnNO;}

PHP reads data from the database and sends it to iOS via JSON I read the database on the PHP side, put the read data into a JSON-formatted string, and then sent to the iOS, but found that the data read all become 1, and then I in the PHP side to determine whether the value of one of the query is a string I know, if the

iOS Development database Chapter-sqlite Common functionsA simple explanation1. Open the Databaseint Sqlite3_open (const char *filename,//file path for databaseSqlite3 **ppdb//DB instance);2. Execute any SQL statementint Sqlite3_exec (sqlite3*,//an open DB instanceconst char *sql,//SQL statement to executeInt (*callback) (void*,int,char**,char**),//callback after the SQL statement is executedvoid *,//The 1th