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Oxford Harrison edited this page Nov 11, 2024 · 25 revisions

DOCSAPIClient API


Run an arbitrary query.

Syntax

client.query(
    query: string | Statement,
    values?: any[],
    options?: QueryOptions
): Promise<QueryResult>;
client.query(
    query: string | Statement, 
    arg2?: {
        values?: any[];
    } & QueryOptions
): Promise<QueryResult>;
client.query(
    arg: {
        query: string | Statement;
        values?: any[];
    } & QueryOptions
): Promise<QueryResult>;
Param Interfaces Description
query Statement An SQL statement (string) or a query instance.
values? - For non-DDL operations, optional values for parameters in the query.
options? QueryOptions Optional extra parameters for the query.
arg2? - Optional argument for a two-parameter call pattern.
arg? Statement Optional argument for a single-parameter call pattern.

Statement

type Statement = 
    | SelectStatement 
    | InsertStatement 
    | UpsertStatement 
    | UpdateStatement 
    | DeleteStatement 
    | CreateDatabase 
    | RenameDatabase 
    | AlterDatabase 
    | DropDatabase
    | CreateTable 
    | RenameTable 
    | AlterTable 
    | DropTable;
➞ Description
Interface Description
SelectStatement A SELECT statement interface.
InsertStatement An INSERT statement interface.
UpsertStatement An UPSERT statement interface.
UpdateStatement An UPDATE statement interface.
DeleteStatement A DELETE statement interface.
CreateDatabase A CREATE DATABASE interface.
RenameDatabase A RENAME DATABASE interface.
AlterDatabase An ALTER DATABASE interface.
DropDatabase A DROP DATABASE interface.
CreateTable A CREATE TABLE interface.
RenameTable A RENAME TABLE interface.
AlterTable An ALTER TABLE interface.
DropTable A DROP TABLE interface.

QueryOptions

interface QueryOptions {
    desc?: string;
    ref?: string;
    noCreateSavepoint?: boolean;
    inspect?: boolean;
}
Param Interfaces Description
desc - Applicable to DDL operations; the commit description.
desc - Applicable to DDL operations; the commit reference.
noCreateSavepoint - Applicable to DDL operations; a directive to disable savepoint creation.
inspect - A directive to log details of the query to the console.

QueryResult

type QueryResult = Array<object| number | Savepoint | boolean | null;
Type Interfaces Description
Array<object> - An array of objects—the standard result type when it's a DQL operation (SELECT), or when it's a DML operation (INSERT, UPDATE, DELETE) with a RETURNING clause.
number - A number indicating total number of rows processed by the query when it's a DML operation without a RETURNING clause.
Savepoint
| boolean
Savepoint The default result type when it's a DDL operation (CREATE, ALTER, DROP, RENAME); the boolean true when savepoint creation has been disabled via options.noCreateSavepoint
Null - The default result type for all other types of query.

Usage

Call patterns

Three-parameter call pattern:

// Each parameter passed distinctly
await client.query(
    `SELECT * FROM users WHERE name = $1`,
    ['John'],
    options
);

Two-parameter call pattern:

// Values passed via second parameter
await client.query(
    `SELECT * FROM users WHERE name = $1`,
    { values: ['John'], ...options }
);

Single-parameter call pattern:

// Everything in an object
await client.query({
    query: `SELECT * FROM users WHERE name = $1`,
    values: ['John'],
    ...options
});

The QueryOptions object

Pass relevant additional options to a query:

// Inspect query in the console
const rows = await client.query(
    `ALTER TABLE users 
    MODIFY COLUMN id int`,
    { desc: 'Query description', inspect: true }
);

Return types

Run a DML operation (CREATE, ALTER, DROP, RENAME) and get back a reference to the savepoint associated with it (See ➞ Automatic-Schema-Versioning):

// Savepoint as return type
const savepoint = await client.query(
    `ALTER TABLE users
    RENAME TO accounts`
);
console.log(savepoint.versionTag()); // number

await savepoint.rollback(); // true

or a DQL operation (SELECT), and get back a result set:

// Array as return type
const rows = await client.query(
    `SELECT * FROM users
    WHERE id = 4`
);
console.log(rows.length); // 1

or a DML operation (INSERT, UPDATE, DELETE) with a RETURNING clause, and get back a result set:

// Array as return type
const rows = await client.query(
    `INSERT INTO users
    SET name = 'John Doe'
    RETURNING id`
);
console.log(rows.length); // 1

or same DML operation without a RETURNING clause, and get back a number indicating the number of rows processed by the query:

// Number as return type
const rowCount = await client.query(
    `INSERT INTO users
    SET name = 'John Doe'`
);
console.log(rowCount); // 1
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