If you never want to have duplicates, you should declare this as a table constraint: CREATE TABLE bookmarks( users_id INTEGER, lessoninfo_id INTEGER, UNIQUE(users_id, lessoninfo_id) ); (A primary key over both columns would have the same effect.) It is then possible to tell the database that you want to silently ignore records that would violate such … Read more
SQLite has had to sacrifice other characteristics that some people find useful, such as high concurrency, fine-grained access control, a rich set of built-in functions, stored procedures, esoteric SQL language features, XML and/or Java extensions, tera- or peta-byte scalability, and so forth Source : Appropriate Uses For SQLite
If most of those concurrent accesses are reads (e.g. SELECT), SQLite can handle them very well. But if you start writing concurrently, lock contention could become an issue. A lot would then depend on how fast your filesystem is, since the SQLite engine itself is extremely fast and has many clever optimizations to minimize contention. … Read more
Pretty much down to personal choice. It may make sense to use an extension based on the database scheme you are storing; treat your database schema as a file format, with SQLite simply being an encoding used for that file format. So, you might use .bookmarks if it’s storing bookmarks, or .index if it’s being … Read more
PRAGMA table_info(table_name); This will work for both: command-line and when executed against a connected database. A link for more details and example. thanks SQLite Pragma Command
In windows you can try this program http://www.nirsoft.net/utils/opened_files_view.html to find out the process is handling db file. Try closed that program for unlock database In Linux and macOS you can do something similar, for example, if your locked file is development.db: $ fuser development.db This command will show what process is locking the file: > … Read more
ALTER TABLE SQLite SQLite supports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table. You can: … Read more
Note that as of version 3.25.0 released September 2018 you can now use ALTER TABLE to rename a column. Original “create new and drop old table” answer below. Say you have a table and need to rename “colb” to “col_b”: First create the new table with a temporary name, based on the old table definition … Read more
From http://www.sqlite.org/lang_createtable.html: CREATE TABLE IF NOT EXISTS some_table (id INTEGER PRIMARY KEY AUTOINCREMENT, …);
Have a look at http://sqlite.org/lang_conflict.html. You want something like: insert or replace into Book (ID, Name, TypeID, Level, Seen) values ((select ID from Book where Name = “SearchName”), “SearchName”, …); Note that any field not in the insert list will be set to NULL if the row already exists in the table. This is why … Read more