Struct QueryColumns

Source

pub struct QueryColumns { /* private fields */ }

Expand description

Represents a collection of query columns.

§Example

use safety_postgres::access::sql_base::QueryColumns;

let mut query_columns = QueryColumns::new(false);
query_columns.add_column("schema_name", "table_name", "column_name").unwrap();

let query_text = query_columns.get_query_text();

assert_eq!(query_text, "SELECT schema_name.table_name.column_name FROM main_table_name");

Implementations§

Source §

impl QueryColumns

Source

pub fn new(all_columns: bool) -> Self

Creates a new instance of QueryColumns struct.

§Arguments

all_columns - A boolean value indicating whether all columns should be selected.

Source

pub fn add_column( &mut self, schema_name: &str, table_name: &str, column: &str, ) -> Result<&mut Self, QueryColumnError>

Adds a query selected column to the query.

§Arguments

schema_name - The name of the schema (input “” if there is no schema name or in the same table).
table_name - The name of the table (input “” if there is no table name or in the same table).
column - The name of the column.

§Returns

Returns a mutable reference to Self (the query builder) on success, or a QueryColumnError on failure.

§Errors

An error is returned if:

The all_columns flag is set to true, indicating that all columns will be queried, so setting a specific column is not allowed.
The schema_name, table_name, or column is an invalid string.

§Example

use safety_postgres::access::sql_base::QueryColumns;

let mut query_columns = QueryColumns::new(false);
query_columns.add_column("", "", "id").unwrap().add_column("", "", "username").unwrap();

Source

pub fn get_query_text(&self) -> String

Retrieves the query text for the current instance.

§Returns

A String representing the query text.

§Example

use safety_postgres::access::sql_base::QueryColumns;

let obj = QueryColumns::new(true);
let query_text = obj.get_query_text();
println!("Query Text: {}", query_text);