Struct PostgresAdapter

Source

pub struct PostgresAdapter { /* private fields */ }

Expand description

PostgreSQL database adapter with connection pooling.

Uses deadpool-postgres for connection pooling and tokio-postgres for async queries.

§Example

use fraiseql_core::db::postgres::PostgresAdapter;
use fraiseql_core::db::{DatabaseAdapter, WhereClause, WhereOperator};
use serde_json::json;

// Create adapter with connection string
let adapter = PostgresAdapter::new("postgresql://localhost/mydb").await?;

// Execute query
let where_clause = WhereClause::Field {
    path: vec!["email".to_string()],
    operator: WhereOperator::Icontains,
    value: json!("example.com"),
};

let results = adapter
    .execute_where_query("v_user", Some(&where_clause), Some(10), None)
    .await?;

println!("Found {} users", results.len());

Implementations§

Source §

impl PostgresAdapter

Source

pub async fn new(connection_string: &str) -> Result<Self>

Create new PostgreSQL adapter with default pool configuration.

§Arguments

connection_string - PostgreSQL connection string (e.g., “postgresql://localhost/mydb”)

§Errors

Returns FraiseQLError::ConnectionPool if pool creation fails.

§Example

let adapter = PostgresAdapter::new("postgresql://localhost/mydb").await?;

Source

pub async fn with_pool_config( connection_string: &str, _min_size: usize, max_size: usize, ) -> Result<Self>

Create new PostgreSQL adapter with custom pool configuration.

§Arguments

connection_string - PostgreSQL connection string
min_size - Minimum size hint (not enforced by deadpool-postgres)
max_size - Maximum number of connections in pool

§Errors

Returns FraiseQLError::ConnectionPool if pool creation fails.

§Note

min_size is accepted for API compatibility but deadpool-postgres uses lazy initialization with dynamic pool sizing up to max_size.

Source

pub async fn with_pool_size( connection_string: &str, max_size: usize, ) -> Result<Self>

Create new PostgreSQL adapter with custom pool size.

§Arguments

connection_string - PostgreSQL connection string
max_size - Maximum number of connections in pool

§Errors

Returns FraiseQLError::ConnectionPool if pool creation fails.

Source

pub fn pool(&self) -> &Pool

Get a reference to the internal connection pool.

This allows sharing the pool with other components like PostgresIntrospector.

Source

pub async fn execute_with_projection( &self, view: &str, projection: Option<&SqlProjectionHint>, where_clause: Option<&WhereClause>, limit: Option<u32>, ) -> Result<Vec<JsonbValue>>

Execute query with SQL field projection optimization.

Uses the provided SqlProjectionHint to generate optimized SQL that projects only the requested fields from the JSONB column, reducing network payload and JSON deserialization overhead.

§Arguments

view - View/table name to query
projection - Optional SQL projection hint with field list
where_clause - Optional WHERE clause for filtering
limit - Optional row limit

§Returns

Vector of projected JSONB rows with only the requested fields

§Errors

Returns FraiseQLError::Database on query execution failure.

§Example

let projection = SqlProjectionHint {
    database: "postgresql".to_string(),
    projection_template: "...".to_string(),
    estimated_reduction_percent: 75,
};

let results = adapter
    .execute_with_projection("v_user", Some(&projection), None, Some(10))
    .await?;