SQLtietokantatauluja

SQLtietokantatauluja, known in English as SQL database tables, are the fundamental building blocks of relational databases. A table is a structured collection of data organized into rows and columns. Each row represents a single record or entity, while each column represents an attribute or characteristic of that entity. For example, in a customer table, each row would represent a unique customer, and columns might include customer ID, name, address, and phone number.

The structure of a table is defined by its schema, which specifies the name of the table and the names and data types of each column. Data types dictate the kind of information a column can hold, such as text, numbers, dates, or booleans. SQL (Structured Query Language) is used to create, manipulate, and query these tables. Commands like CREATE TABLE are used to define the table structure, INSERT INTO adds new rows, UPDATE modifies existing data, and DELETE removes rows. SELECT is the primary command for retrieving data from one or more tables. Relationships can be established between tables using keys, allowing for complex data retrieval and management. Understanding SQL database tables is crucial for anyone working with relational databases.