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I have a very large table (30 million rows), and I want to load it as a data frame in R. read.table() has many convenient functions, but it seems that there are many logic in the implementation that will slow things down. As far as I'm concerned, I'm assuming that I know the type of column in advance, that the table doesn't contain any column ...

FMDB is generally used for data saving in iOS. Generally, fields will not be modified or added after being defined. If it is strict, we need to add the function of adding fields to the database. At present, FMDB and FMDB migration manager are used in the project to save the database version number and upgrade the database Acco ...

1. Use execSQL API to operate the database. Step 1: create the Class MyOpenHelper implementation interface SQLiteOpenHelper, copy the constructor, onCreate and onUpgrade methods; Step 2, after creating the myOpenHelper object myOpenHelper, use the relevant API of myOpenHelper to operate the database. package com.xiaohui.create ...

Using pageoffice to realize document online editing and document flow 1: process Draft documents in the modified traceless mode, open them in the forced trace mode when leaders annotate their opinions, open them in the approval mode when the clerk cleans up the draft, and open the released official documents in the final read-only mode. Amon ...

Autodesk Forge Viewer to truly implement stand-alone offline application) About the offline implementation of Autodesk Forge Viewer, the official has allowed exporting SVF and related documents, allowing users to deploy SVF and other documents to private servers, but this paper discusses another requirement. The customer requi ...

Fabric CA is a certificate management tool of Hyperledger Fabric, which is very convenient for development and testing. In this tutorial, we will explore the use of fabric Ca and use it to complete user registration / Register and registration / Enrollment. Hyperledger Fabric is a licensed blockchain platform. Before accessing the Fabric networ ...

The article was forwarded from the professional Laravel developer community with the original link: https://learnku.com/laravel/t... If you use Laravel For a while, you should have heard a lot about multiple identities.You should also have heard a lot about certification watchers.However, if you are unfamiliar with Laravel, multiple authentic ...

sqlite3_open SQLite3 open function prototype: int sqlite3_open( const char *filename, /* Database filename (UTF-8) */ sqlite3 **ppDb /* OUT: SQLite db handle */ ); SQLite3 open is used to connect and open a database. If the database does not exist, a database file will be created and opened under the specified ...

Links to the original text: https://my.oschina.net/gal/blog/200185 This job is mainly to investigate the use of SQLite, get the information of mobile contacts (name, cell phone number, ...

Recently, I plan to transfer my blog to the typecho platform and choose a theme that I personally prefer. Akina for Typecho Theme Template Thank you for the open source sharing of the theme, but there was a "500 Database Query Error" problem at the beginning of the use process.Add the following code at the beginning of the index.php f ...