3/21/2024 0 Comments Sqlite android database exampleIn the next section, you download the starter data set and learn more about its schema. The tables in a database and the columns in each table are collectively known as the schema. The following table maps common Kotlin data types to their SQLite equivalents. SQLite databases use data types too! Data table columns must have a specific data type. In Kotlin, you're familiar with data types like Int and Boolean. Examples of NoSQL databases include Redis or Cloud Firestore. Other kinds of databases, known as NoSQL, are structured similarly to a JSON object with nested pairs of keys and values. Note: Not all databases are organized into tables, columns, and rows. SQL is simply a way to add and retrieve data from a relational database with a few lines of code. You won't have to learn C or any entirely new programming language to work with a relational database. Specifically, SQLite refers to a lightweight C library for relational database management with Structured Query Language, known as SQL and sometimes pronounced as "sequel" for short. SQLite is a commonly used relational database. For the example above, that means you name the tables teacher, student, and course, not the plural forms of teachers, students, and courses. Note: Like with Kotlin classes, the convention is to use the singular form for the name of database tables. The presence of a foreign key means there's a relationship between the tables. When a table references the primary key of another table, it is known as a foreign key. This identifier is known as the primary key. For example, a graduate student might have a single professor as a doctoral advisor whereas that professor is the doctoral advisor for multiple students.Įvery table in a relational database contains a unique identifier for rows, such as a column where the value in each row is an automatically incremented integer. A database is called a relational database when it can model relationships between tables. Just as a spreadsheet can contain multiple sheets and an app can contain multiple classes, a database can contain multiple tables. Objects contain values for each property defined in the class, just as rows contain values for each column defined in the data table.
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