- #Android studio sqlite autoincrement integer non primary key install
- #Android studio sqlite autoincrement integer non primary key code
#Android studio sqlite autoincrement integer non primary key install
Stores the users\computers that are allowed to run the post install actions Postinstall - a list of activities to perform when the main install has finished. Platform - the OS architecture the installer file is compiled for. Package - stores the type of installer, NSIS, Inno Nullsoft etc. Stores the user or computer to install the program for or on. Installer - this is the main table that has relationships with the other tables and stores info about the installer file, install order etc. I have attached the database thus far and the tables function are as follows:-Ĭategory - stores text describing the general usage the installer comes under, such as Browser, Compression etc. The database is going to store information about setup installers, such as paths, installer specific info, users to install for, type and category of installer blah, blah. I am using SQLite Expert to design the database and test sql queries.
Package import import .InstrumentationRegistry import .runners.AndroidJUnit4 import am trying to normalise a database to remove duplicate info. Package import import import .runners.AndroidJUnit4 import .InstrumentationRegistry import .assertThat import import import import import java.util.* ( AndroidJUnit4 :: class ) class CompositeKeyEntityTest In that case, you could have something like:
#Android studio sqlite autoincrement integer non primary key code
One approach has all versions of the same entity in the same table, with a version code attached to the “natural” primary key to identify a specific version of that content. There are several ways of implementing data versioning. One scenario for this is data versioning, where we are tracking changes to data over time, the way a version control system tracks changes to source code and other files over time. In that case, you can skip the annotation and use the primaryKeys property of the annotation. However, it may be that they should be individual properties in your entity, but they happen to combine to create the primary key. If, logically, those are all part of a single object, you could combine them into a single property, as we will see in the next chapter. This is particularly true if you are trying to design your entities around an existing database structure, one that used a composite primary key for one of its tables (for whatever reason). In some cases, you may have a composite primary key, made up of two or more columns in the database.
For your production apps, you will need to decide if the headaches surrounding database-generated identifiers are worth their benefits. While these take up much more room than a simple Long, they can be uniquely generated outside of the database. Some of the samples in this book will use a UUID instead. This presents “trickle-down” complications - for example, you cannot make the primary key property be val, as then you cannot create an instance of an entity that is not yet in the database. MiscSamples/src/androidTest/java/com/commonsware/room/misc/AutoGenerateEntityTest.kt) In Room, if you have an Long property that is your you can optionally apply AUTOINCREMENT to the corresponding column by adding autoGenerate=true to the annotation: In SQLite, if you have an INTEGER column identified as the PRIMARY KEY, you can optionally have SQLite assign unique values for that column, by way of the AUTOINCREMENT keyword. If you have a single field that is the primary key for your entity, using the annotation is simple and helps you clearly identify that primary key at a later point. Some - though probably not all - of these features will be of interest in larger apps. However, there is a fair bit that is “above and beyond that”. Anything above and beyond that is optional. The only absolute requirements for a Room entity class is that it be annotated with the annotation and have a field identified as the primary key, typically by way of a annotation. This is a library module with a variety of entities and DAOs, all tied into a MiscDatabase, with instrumented tests for each of the entities. Many of the code snippets shown in this chapter come from the the MiscSamples module of the book’s primary sample project, sample project. In this chapter, we will start to explore the rest of the configuration for entities and DAOs. However, we only scratched the surface of what can be configured on entities and DAOs.
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