@jsh/db

Client

The database client.

Usage example

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const db = require("@jsh/db");
const client = new db.Client();
try {    
    conn = client.connect();
    rows = conn.query("select * from example limit 10")
    cols = rows.columns()
    console.log("cols.names:", JSON.stringify(cols.columns));
    console.log("cols.types:", JSON.stringify(cols.types));
    
    count = 0;
    for (const rec of rows) {
        console.log(...rec);
        count++;
    }
    console.log("rows:", count, "selected" );
} catch(e) {
    console.log("Error:", e);
} finally {
    if (rows) rows.close();
    if (conn) conn.close();
}

Creation

If neither bridge nor driver is specified, the client defaults to connecting to the internal Machbase DBMS.

Options

• Options for Drivers

driver and dataSource options support sqlite, mysql, mssql, postgresql and machbase without pre-defined bridge.

• Options for Bridge

It is also possible to create Client with predefined bridge.

Properties

connect()

connect to the database.

Return value

• Object Conn

Conn

close()

disconnect to the database and release

Syntax

close()

query()

Syntax

query(String *sqlText*, any ...*args*)

Return value

• Object Rows

queryRow()

Syntax

queryRow(String *sqlText*, any ...*args*)

Return value

• Object Row

exec()

Syntax

exec(sqlText, ...args)

Parameters

• sqlText String Sql text string
• args any A variable-length list of arguments.

Return value

• Object Result

appender()

Create new “appender”.

Syntax

appender(table_name, ...columns)

Parameters

• table_name String The table name of to append.
• columns String A variable-length list of column names. If columns is omitted, all columns of the table will be appended in order.

Return value

• Object Appender

Rows

Rows encapsulates the result set obtained from executing a query.

It implements Symbol.iterable, enabling support for both patterns:

for(rec := rows.next(); rec != null; rec = rows.next()) {
    console.log(...rec);
}

for (rec of rows) {
    console.log(...rec);
}

close()

Release database statement

Syntax

close()

Parameters

None.

Return value

None.

next()

fetch a record, returns null if no more records

Syntax

next()

Parameters

None.

Return value

• any[]

columns()

Syntax

columns()

Parameters

None.

Return value

• Object Columns

columnNames()

Syntax

columnNames()

Parameters

None.

Return value

• String[]

columnTypes()

Syntax

columnTypes()

Parameters

None.

Return value

• String[]

Row

Row encapsulates the result of queryRow which retrieve a single record.

columns()

Syntax

columns()

Parameters

None.

Return value

• Object Columns

columnNames()

names of the result

Syntax

columnNames()

Parameters

None.

Return value

• String[]

columnTypes()

types of the result

Syntax

columnTypes()

Parameters

None.

Return value

• String[]

values()

result columns

Syntax

values()

Parameters

None.

Return value

• any[]

Result

Result represents the outcome of the exec() method, providing details about the execution.

Properties

Columns

Properties

Appender

append()

Invoke the append method with the specified values in the order of the columns.

Syntax

append(...values)

Parameters

• values any The values to be appended to the table, provided in the order of the specified columns.

Return value

None.

close()

Close the appender.

Syntax

close()

Parameters

None.

Return value

None.

result()

Returns the result of the append operation after the appender is closed.

Syntax

result()

Parameters

None.

Return value

• Object