sqlite

问题 This question already has answers here : When does SQLiteOpenHelper onCreate() / onUpgrade() run? (15 answers) Make sure the Cursor is initialized correctly before accessing data from it (7 answers) Closed 4 years ago . I have designed a database. Here is my code: Cursor cursor =database.query(ColumnID.AGENT_TABLE,null,null,null,null,null,null); while (cursor.moveToNext()) { County county = new County(); county.setId(cursor.getString(cursor .getColumnIndex(ColumnID.ID))); county.setAgent_Name

问题 This question already has answers here : Why Android app crashes for initializing variable with findViewById(R.id.******) at the beginning of the class? (4 answers) What is a NullPointerException, and how do I fix it? (12 answers) Closed 1 year ago . I'm building a simple multi-activity list app to practice with SQLite. I was trying to get the strings from the database to display in the listview when this started. I'm getting the error java.lang.NullPointerException: Attempt to invoke virtual

问题 People, How Can I Zip my iOS app's sqlite database? Because I'm trying to sinc it with the cloud but im having some troubles... Which classes I'm supposed to use to zip it ? please help me out! 回答1: You can use ZipArchive, its a objective c wrapper to zip/unzip - http://code.google.com/p/ziparchive/ for zip :- NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* dPath = [paths objectAtIndex:0]; NSString* txtfile = [dPath

问题 I'm trying to get Entity Framework (6.4.4. the newest version in summer 2020) working together with SQLite (1.0.113.1, also latest in summer 2020). I found a lot of information about how to do this, but this information was not always helpful, quite often they contradicted each other. Now that I found out how to do it, I decided to jot down how I did it. The question describes the classes and the tables, the answer will describe how to do it. I describe a database for Schools, where every

问题 I have one group table with a recursive relation, so each record has a parent_id . Given a group, I need to get all the student (each belong to a group) names in all its subgroups, but ordered by student name. Do you know if there is any "easy" way to do it? If I have to do multiple queries, then I should order the results of the different Cursors, but Cursor has no orderBy(). Any ideas? Thank you so much! 回答1: As SQLite does not support recursive queries I implemented the select with two

问题 I have one group table with a recursive relation, so each record has a parent_id . Given a group, I need to get all the student (each belong to a group) names in all its subgroups, but ordered by student name. Do you know if there is any "easy" way to do it? If I have to do multiple queries, then I should order the results of the different Cursors, but Cursor has no orderBy(). Any ideas? Thank you so much! 回答1: As SQLite does not support recursive queries I implemented the select with two

问题 I have trouble with installing sqlite3 in electron 8.1 I got following errors Error: Cannot find module 'D:\TASK(2020.1.1~)\AMS\node_modules\sqlite3\lib\binding\electron-v8.1-win32-x64\node_sqlite3.node' Require stack: - D:\TASK(2020.1.1~)\AMS\node_modules\sqlite3\lib\sqlite3.js - D:\TASK(2020.1.1~)\AMS\main.js - D:\TASK(2020.1.1~)\AMS\node_modules\electron\dist\resources\default_app.asar\main.js - at Module._resolveFilename (internal/modules/cjs/loader.js:798:15) at Function../lib/common

问题 I have trouble with installing sqlite3 in electron 8.1 I got following errors Error: Cannot find module 'D:\TASK(2020.1.1~)\AMS\node_modules\sqlite3\lib\binding\electron-v8.1-win32-x64\node_sqlite3.node' Require stack: - D:\TASK(2020.1.1~)\AMS\node_modules\sqlite3\lib\sqlite3.js - D:\TASK(2020.1.1~)\AMS\main.js - D:\TASK(2020.1.1~)\AMS\node_modules\electron\dist\resources\default_app.asar\main.js - at Module._resolveFilename (internal/modules/cjs/loader.js:798:15) at Function../lib/common

问题 I am trying to learn LINQ with LINQPad, but the fact is that I have a notebook. Therefore, I don't want to install SQL Server on it (I am not even conviced that I could do it). Some LINQPAD Examples use a database called nutshell.mdf, I'd like to know if I can find a SQLite version of this database, and where? 回答1: There's no SQLite version, but you can create a SQL CE edition easily enough. SQL CE is fairly lightweight and won't bog down your notebook. LINQPad supports SQL CE: click "Add

问题 I have a dictionary that I want to add all the values to an sqlite database. All the keys in the dictionary exist in the database, and all the keys are of type string. Yet, I am having trouble with getting the values into the database. The following code is ugly, insecure, and errors whenever it comes across a string with a " in it, but it sort of works. Query="INSERT INTO packages VALUES(" for tag in Tags: Query=Query + '"' + Package[tag] + '", ' Query=Query[:-2]+")" cursor.execute(Query)