Struct SelectBuilder 

pub struct SelectBuilder<I> { /* private fields */ }

Available on crate feature rdbc only.

Fluent builder for SQL SELECT statements used by RDBC item readers.

Call SelectBuilder::from to create a builder for a given table, chain optional filter/order methods, then call SelectBuilder::build_sql to obtain the final SQL string.

Type Parameters

• I — The item type that will be read from the database. Used only for the keyset key function; when keyset pagination is not needed I can be any type (e.g. a unit struct).

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Product;

let sql = SelectBuilder::<Product>::from("products")
    .columns(&["id", "name", "price"])
    .where_gte("price", 10.0_f64)
    .where_eq("active", true)
    .order_by_desc("price")
    .build_sql();

assert!(sql.starts_with("SELECT id, name, price FROM products WHERE"));
assert!(sql.contains("ORDER BY price DESC"));

Implementations

impl<I> SelectBuilder<I>

pub fn from(table: impl Into<String>) -> Self

Creates a new SelectBuilder targeting the given table.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("orders").build_sql();
assert_eq!(sql, "SELECT * FROM orders");

pub fn columns(self, cols: &[&str]) -> Self

Specifies the columns to select.

When not called (or called with an empty slice), the query uses SELECT *.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("users")
    .columns(&["id", "email"])
    .build_sql();

assert_eq!(sql, "SELECT id, email FROM users");

pub fn where_eq(self, col: &str, val: impl Into<ConditionValue>) -> Self

Adds a col = val condition.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("users")
    .where_eq("status", "ACTIVE")
    .build_sql();

assert_eq!(sql, "SELECT * FROM users WHERE status = 'ACTIVE'");

pub fn where_not_eq(self, col: &str, val: impl Into<ConditionValue>) -> Self

Adds a col != val condition.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("users")
    .where_not_eq("role", "ADMIN")
    .build_sql();

assert_eq!(sql, "SELECT * FROM users WHERE role != 'ADMIN'");

pub fn where_gt(self, col: &str, val: impl Into<ConditionValue>) -> Self

Adds a col > val condition.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("orders")
    .where_gt("amount", 100_i32)
    .build_sql();

assert_eq!(sql, "SELECT * FROM orders WHERE amount > 100");

pub fn where_gte(self, col: &str, val: impl Into<ConditionValue>) -> Self

Adds a col >= val condition.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("orders")
    .where_gte("score", 4.5_f64)
    .build_sql();

assert!(sql.starts_with("SELECT * FROM orders WHERE score >= "));

pub fn where_lt(self, col: &str, val: impl Into<ConditionValue>) -> Self

Adds a col < val condition.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("items")
    .where_lt("stock", 10_i32)
    .build_sql();

assert_eq!(sql, "SELECT * FROM items WHERE stock < 10");

pub fn where_lte(self, col: &str, val: impl Into<ConditionValue>) -> Self

Adds a col <= val condition.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("items")
    .where_lte("rank", 100_i32)
    .build_sql();

assert_eq!(sql, "SELECT * FROM items WHERE rank <= 100");

pub fn where_like(self, col: &str, pat: &str) -> Self

Adds a col LIKE 'pattern' condition.

Single quotes in pat are escaped automatically.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("users")
    .where_like("email", "%@corp.com")
    .build_sql();

assert_eq!(sql, "SELECT * FROM users WHERE email LIKE '%@corp.com'");

pub fn where_is_null(self, col: &str) -> Self

Adds a col IS NULL condition.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("users")
    .where_is_null("deleted_at")
    .build_sql();

assert_eq!(sql, "SELECT * FROM users WHERE deleted_at IS NULL");

pub fn where_is_not_null(self, col: &str) -> Self

Adds a col IS NOT NULL condition.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("users")
    .where_is_not_null("confirmed_at")
    .build_sql();

assert_eq!(sql, "SELECT * FROM users WHERE confirmed_at IS NOT NULL");

pub fn order_by_asc(self, col: &str) -> Self

Appends an ORDER BY col ASC clause.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("users")
    .order_by_asc("created_at")
    .build_sql();

assert_eq!(sql, "SELECT * FROM users ORDER BY created_at ASC");

pub fn order_by_desc(self, col: &str) -> Self

Appends an ORDER BY col DESC clause.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("users")
    .order_by_desc("score")
    .build_sql();

assert_eq!(sql, "SELECT * FROM users ORDER BY score DESC");

pub fn order_by_keyset( self, col: &str, key_fn: impl Fn(&I) -> String + 'static, ) -> Self

Configures keyset (cursor-based) pagination on col.

Clears any previously configured ORDER BY clauses, sets ORDER BY col ASC, and stores col and key_fn for use by the reader at runtime.

key_fn extracts the cursor value (as a String) from the last item returned by a page, so the next page can request WHERE col > last_cursor.

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Event { id: i64 }

let sql = SelectBuilder::<Event>::from("events")
    .order_by_keyset("id", |e: &Event| e.id.to_string())
    .build_sql();

assert_eq!(sql, "SELECT * FROM events ORDER BY id ASC");

pub fn build_sql(&self) -> String

Builds and returns the SQL SELECT statement.

• If no columns were specified, emits SELECT *.
• Multiple WHERE conditions are joined with AND.
• Multiple ORDER BY clauses are joined with , .

Examples

use spring_batch_rs::item::rdbc::SelectBuilder;

struct Row;

let sql = SelectBuilder::<Row>::from("orders")
    .columns(&["id", "total"])
    .where_eq("status", "OPEN")
    .where_gt("total", 0_i32)
    .order_by_asc("id")
    .build_sql();

assert_eq!(
    sql,
    "SELECT id, total FROM orders WHERE status = 'OPEN' AND total > 0 ORDER BY id ASC"
);