Database Schema

A database schema is the blueprint of a database: the tables, columns, data types, keys, indexes, views, and constraints that define how data is organized. In some systems, such as PostgreSQL, a schema is also a namespace that groups objects inside a database.

Why it matters

The schema is the contract between your data and your application. A strict schema catches bad data at write time and documents the data model. Changing it on a live system needs care, which is why teams use versioned migrations. Schemaless databases move that contract into application code rather than removing it.

Example

CREATE TABLE products (
  id    BIGINT PRIMARY KEY,
  title TEXT NOT NULL,
  price NUMERIC(10,2) CHECK (price >= 0)
);

This defines the columns, types, a key, and a rule that prices cannot be negative.

Common mistakes

• Editing the production schema by hand, so environments drift apart and nobody knows the true state.
• Using overly generic columns like data1, data2 that hide meaning.
• Confusing the two meanings of the word: the overall design versus a namespace object.

Related

• Database migration
• Database normalization
• Primary key

यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.