MySQL Functions Creating Database and Department Table USE UNIVERSITY_DB; CREATE TABLE departments( dept_name VARCHAR(20), budget BIGINT(20), building VARCHAR(20) ); INSERT INTO departments VALUES('Electrical Engineering',15000,'Building A'); INSERT INTO departments VALUES('Telecommunications',45000...
Core Concepts JDBC (Java Database Connectivity) is a standardized Java API for interacting with relational databases. Database vendors provide JDBC-compliant drivers—typically distributed as JAR files—that implement this interface. To connect to a specific database, the corresponding driver must be...
Global LockingGlobal locks restrict the entire database instance to a read-only state, preventing any data modification operations (insert, update, or delete) while the lock is active. This is often used for maintenance tasks or consistent backups.-- Acquire a global read lock FLUSH TABLES WITH READ...
Conditional Query Execution Execute queries only when parameter are not empty: SELECT * FROM t_interlinkage WHERE IF('翁二翁' != '', name LIKE '%翁二翁%', 1=1); Enhanced fuzzy search with concatenation: SELECT * FROM t_interlinkage WHERE IF('翁二翁' != '', name LIKE CONCAT('%', '翁二翁', '%'), 1=1); Comma-Separ...
Network Communication The network module enables applications to perform HTTP requests, establish WebSocket connections, and manage socket-based data transfers. Making HTTP Requetss To initiate an HTTP request: import http from '@ohos.net.http'; const client = http.createHttp(); client.request( 'htt...
Genarel SQL Syntax Rules SQL statements can span single or multiple lines, terminating with a semicolon Whitespace and indentation improve readability without affecting execution MySQL is case-insensitive for keywords (though uppercase is conventional) Comment syntax: Single-line: -- comment or # co...
Transactions Transaction Definition and ACID Properties Definition: A sequence of database operations that must either all succeed or all fail, serving as an indivisible unit of work. ACID Properties: Atomicity: All operations within a transaction are completed successfully; otherwise, none are appl...
Database Record Detection in JavaScript Process Overview The following steps outline the approach to check for database records using JavaScript: Step Action 1 Establish database connection 2 Query database records 3 Verify record existence 4 Return verification result Implementation Details Step 1:...
Fundamental Database Concepts Index Column Limits A single index in MySQL can encompass a maximum of 16 columns. Storage Engines MySQL utilizes storage engines to manage data storage, indexing, and retrieval mechanisms. The primary engines include: InnoDB: The default engine since version 5.5.5. It...
Lombok streamlines Java development by generating boilerplate code at compile time through annotations. To integrate it, add the following dependency: <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <scope>provided</scope> &...
