sqlite | 易学教程

Android : SQLite 版学生系统

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在 Android : ListView 学生管理中已经使用 ListView 控件实现简易学生管理功能，现在尝试采用 SQLite 数据库本地保存学生信息，并完善查询功能。使用工具 android studio (ver. 3.5.1) android（sdk 29) java(ver.1.8.0) gradle(ver. 5.4.1) 功能实现 1.创建学生实体类。 public class StuInfo implements Serializable { private String name; private String major; private String age; private String sex; private String kecheng; private String academy; private String date; private int id; ······ 2.设计一个的列表来显示学生信息。 3.创建 MySQLiteAccess 类访问数据库。 public class MySQLiteAccess extends SQLiteOpenHelper { /** * @param context：上下文 * @param version：版本号 */ public MySQLiteAccess(Context context,

django启动时提示SQLite 3.8.3 or later is required

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提示这个信息，是因为django3需要的SQLite版本需要升级参考帖子： https://blog.csdn.net/qq_39969226/article/details/92218635 来源： https://www.cnblogs.com/xiaxiaoxu/p/12221987.html

Rails 3. Nested transactions. Exception in a child block

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问题 Why doesn't ActiveRecord rollback changes in nested transactions after exception was risen in a child block? Here are examples: 1. >> Client.transaction do ?> Client.create(:name => 'Pavel') >> Client.transaction do ?> Client.create(:name => 'Elena') >> raise ActiveRecord::Rollback >> end >> end => nil >> Client.all.map(&:name) => ["Pavel", "Elena"] # instead of [] 2. >> Client.transaction do ?> Client.create(:name => 'Pavel') >> Client.transaction(:requires_new => true) do ?> Client.create(

Rails 3. Nested transactions. Exception in a child block

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How to store json data in sqlite

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问题 Im hard pressed to store data as 'JSON' format into my sqlite database for an rails application. I have searched for how to store data as JSON in my sqlite database but am not seeing many alternatives which are promising. Any one who can guide me on how this can be done? 回答1: You need to generate a string from your JSON and then save that string in your database as a regular string. require 'json' my_hash = {:hello => "goodbye"} puts JSON.generate(my_hash) => "{\"hello\":\"goodbye\"}" When

sqlite + PyQt5 to standalone exe - Python 3.6.3 + Pyinstaller

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问题 I would like to create an exe with Pyinstaller including a database (.db) and a picture (.png). I want everything into a single exe ( --onefile ). I tried to add the path of both elements directly in the spec file but it doesn't work. Here is my spec file: # -*- mode: python -*- block_cipher = None a = Analysis(['back_end.py'], pathex=['C:\\Users\\...\\site-packages\\PyQt5\\Qt\\bin', 'C:\\Users\\...\\Test_packaging'], binaries=[], datas=['C:\\Users\...\\Test_packaging\\database1.db', 'C:\

Custom SQLite functions in Xamarin.iOS

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问题 I am working on custom function of Sqlite on Xamarin.iOS. I got answer from here : Show markers on map within a given radius (Xamarin.Android) but I am running into issue of Attempting to JIT compile method '(wrapper native-to-managed) Mono.Data.Sqlite.SqliteFunction:ScalarCallback (intptr,int,intptr)' while running with --aot-only. After searching on stack I found that here is a solution: custom functions SQLite with Mono but solution mention there is tough for me to understand. I am not

SQLite iOS Insert data

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问题 Im trying to insert just one name to my sqlite file. im using this code but it's not working :/ -(void)InsertRecords:(NSMutableString *) txt{ if(addStmt == nil) { const char *sql = "INSERT INTO myMovies (movieName) VALUES(?) "; if(sqlite3_prepare_v2(database, sql, -1, &addStmt, NULL) != SQLITE_OK) NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(database)); else sqlite3_bind_text(addStmt, 1, [txt UTF8String], -1, SQLITE_TRANSIENT); } if(SQLITE_DONE != sqlite3_step

sqlite3 database is getting locked

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问题 I am creating an application with sqlite. I am performing all kind of task on the database Insert, Update, Delete, Select . For that I open the database every time, Then execute my query using sqlite3_step() and after the result I use sqlite3_finalize() and sqlite3_close() methods. It is working well in most cases. I am not getting when its happening but some times my database gets locked with the same process I follow and some time it works. I need to unlock database so even in any case my

sqlite database in persian language

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问题 I tried to create a sqlite database from a csv file. I did it as it is said in this page : using your own sqlite db in android and this : import csv to sqlite but the problem is when the table contains data in farsi/arabic language. sqlite shows that character as "_". what should I do? PS. I want to use this DB in an android project. edit: I import csv to sqlite using this code: CREATE TABLE "android_metadata"("locale" TEXT DEFAULT 'en_US'); CREATE TABLE "addresses"(_id integer PRIMARY KEY,