NodeJS¶

@croosdb/crossdb-nodejs

APIs List¶

new¶

Open a connection and create/open a local Database.

const CrossDB = require("@croosdb/crossdb-nodejs");

const db = new CrossDB(":memory:");
// or
const db = new CrossDB("[path/]db_name");

• If path is :memory:, a memory database is created or opened, becoming the default database for this connection.
• If path specifies [path/]db_name, a database at the given path is created or opened.
• All databases opened are shared across all active connections.

exec¶

Execute SQL statement and return result set.

// Create tables if they do not already exist
db.exec(
  "CREATE TABLE IF NOT EXISTS student (id INT PRIMARY KEY, name CHAR(16), age INT, class CHAR(16), score FLOAT, info VARCHAR(255))"
);
// Clean (empty) a table
db.exec("DELETE FROM student");
// Insert sample data into the table
db.exec(
  "INSERT INTO student (id,name,age,class,score) VALUES (1,'jack',10,'3-1',90),(2,'tom',11,'2-5',91),(3,'jack',11,'1-6',92),(4,'rose',10,'4-2',90),(5,'tim',10,'3-1',95)"
);
// Query to select all records from the table

let res = db.exec("SELECT * FROM student");
res.forEach((element, i) => {
  console.log(i, "Select all records: ", element);
});
// Execute multiple statements
res = db.exec(
  "SELECT COUNT(*) as Count FROM student; SELECT id, name, age FROM student WHERE id=2;SELECT MIN(score) as min, MAX(score) as max, SUM(score) as sum, AVG(score) as avg FROM student"
);
res.forEach((element, i) => {
  console.log(i, "Multi-statement result: ", element);
});

In SQL, the behavior of statements regarding result sets is as follows:

• SELECT Statements: These retrieve data and return a result set comprising the selected rows.
• Non-SELECT Statements: Statements like INSERT, UPDATE, and DELETE modify data and typically do not return a result set. Instead, they provide the number of rows affected.

When executing multiple statements sequentially:

• Multiple SELECT Statements: Each SELECT returns its own result set in the order of execution.
• Mixed Statements: Only SELECT statements return result sets, each corresponding to its position in the sequence. Non-SELECT statements do not return result sets but indicate the number of rows affected.

begin¶

Begin a transaction.

begin();

commit¶

Commit a transaction.

commit();

rollback¶

Rollback a transaction.

rollback();

close¶

Close connection.

close();

version¶

Get CrossDB version string.

version();

Return this object:

• "CroosDB": CroosDB version.
• "Package": Node.js package version,
• "Platform": Platform information

{
  "CroosDB": "0.11.0",
  "Package": "1.4.1",
  "Platform": "darwin"
}

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