Struct Conditions

Source

pub struct Conditions { /* private fields */ }

Expand description

Represents a set of conditions to be used in an execution.

§Example

use safety_postgres::access::conditions::ComparisonOperator::{Equal, Lower};
use safety_postgres::access::conditions::Conditions;
use safety_postgres::access::conditions::IsInJoinedTable::{No, Yes};
use safety_postgres::access::conditions::LogicalOperator::{And, FirstCondition};

let mut conditions = Conditions::new();

conditions.add_condition("column1", "condition1", Equal, FirstCondition, No).expect("add condition failed");
conditions.add_condition("column2", "condition2", Lower, And, Yes{
    schema_name: "schema_name".to_string(), table_name: "table_name".to_string()
}).expect("add condition failed");

assert_eq!(
    conditions.get_condition_text(),
    "column1 = condition1 AND schema_name.table_name.column2 < condition2")

And you can specify the condition more intuitive using Conditions.add_condition_from_str(column, value, condition_operator, condition_chain_operator, is_joined_table_condition) method.

use safety_postgres::access::conditions::{Conditions, IsInJoinedTable};

let mut conditions = Conditions::new();

conditions.add_condition_from_str(
    "column1",
    "condition1",
    "eq",
    "", IsInJoinedTable::No).expect("add failed");
conditions.add_condition_from_str(
    "column2",
    "condition2",
    ">=",
    "or",
    IsInJoinedTable::Yes{
        schema_name: "schema_name".to_string(), table_name: "table_name".to_string()
    }).expect("add failed");

assert_eq!(
    conditions.get_condition_text(),
    "column1 = condition1 OR schema_name.table_name.column2 >= condition2")

Implementations§

Source §

impl Conditions

Source

pub fn new() -> Self

Creates a new empty Conditions instance.

Source

pub fn add_condition_from_str( &mut self, column: &str, value: &str, comparison_operator: &str, condition_chain_operator: &str, is_joined_table_condition: IsInJoinedTable, ) -> Result<&mut Self, ConditionError>

Adds a condition based on the input string parameters.

§Arguments

column - The name of the column to compare.
value - The value to compare against.
comparison_operator - The operator to use for the comparison.
- Available operator:
 - Equal: “=”, “equal”, “eq”
 - Greater: “>”, “greater”, “gt”
 - GreaterEqual: “>=”, “greater_equal”, “ge”, “greater_eq”
 - Lower: “<”, “lower”, “lt”
 - LowerEqual: “<=”, “lower_equal”, “le”, “lower_eq”
condition_chain_operator - The operator to use for chaining multiple conditions.
- Available operator:
  - FirstCondition(there is no previous condition): “”, “first”, “none”
  - And: “and”, “&”
  - Or: “or”, “|”
is_joined_table_condition - Whether the condition is for a joined table.

§Errors

Returns a ConditionError if there’s an error in the input parameters.

§Examples

use safety_postgres::access::conditions::Conditions;
use safety_postgres::access::conditions::IsInJoinedTable::No;

let mut conditions = Conditions::new();
conditions
    .add_condition_from_str("name", "John", "=", "first", No)
    .expect("adding condition failed");
conditions
    .add_condition_from_str("age", "40", "le", "or", No)
    .expect("adding condition failed");

assert_eq!(conditions.get_condition_text(), "name = John OR age <= 40")

Source

pub fn add_condition( &mut self, column: &str, value: &str, comparison: ComparisonOperator, condition_chain: LogicalOperator, is_joined_table_condition: IsInJoinedTable, ) -> Result<&mut Self, ConditionError>

Adds a condition to the query builder.

§Arguments

column - The column name to which the condition is applied.
value - The value for comparison.
comparison - The operator used for comparison.
condition_chain - The logical operator used to chain the conditions.
is_joined_table_condition - Indicates whether the condition is for a joined table or not.

§Returns

A mutable reference to Self (Conditions) if the condition is successfully added, otherwise a ConditionError.

§Examples

use safety_postgres::access::conditions::Conditions;
use safety_postgres::access::conditions::{ComparisonOperator, LogicalOperator, IsInJoinedTable};

let mut conditions = Conditions::new();

let _ = conditions.add_condition(
    "name",
    "John",
    ComparisonOperator::Equal,
    LogicalOperator::FirstCondition,
    IsInJoinedTable::No).expect("add condition failed")
    .add_condition(
    "age",
    "40",
    ComparisonOperator::LowerEq,
    LogicalOperator::Or,
    IsInJoinedTable::No).expect("add condition failed");

assert_eq!(conditions.get_condition_text(), "name = John OR age <= 40");