GoSQLX/pkg/sql/doc.go at main · ajitpratap0/GoSQLX

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// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

// Package sql provides the core SQL parsing infrastructure for GoSQLX, including

// tokenization, parsing, AST generation, and SQL dialect support.

// This package serves as the parent for all SQL-related functionality in GoSQLX,

// organizing the parsing pipeline into cohesive subpackages.

// # Package Architecture

// The sql package is organized into several specialized subpackages:

// - tokenizer: Zero-copy SQL lexical analysis and token generation

// - parser: Recursive descent parser that builds AST from tokens

// - ast: Abstract Syntax Tree node definitions and visitor patterns

// - token: Token type definitions and pool management

// - keywords: SQL keyword categorization and dialect-specific recognition

// - security: SQL injection detection and security pattern scanning

// # SQL Processing Pipeline

// The standard SQL processing pipeline flows through these stages:

// 1. Tokenization (pkg/sql/tokenizer):

// tkz := tokenizer.GetTokenizer()

// defer tokenizer.PutTokenizer(tkz)

// tokens, err := tkz.Tokenize([]byte("SELECT * FROM users"))

// 2. Token Conversion (pkg/sql/parser):

// parserTokens := parser.ParseFromModelTokens(tokens)

// 3. Parsing (pkg/sql/parser):

// p := &parser.Parser{}

// astObj, err := p.Parse(parserTokens)

// defer ast.ReleaseAST(astObj)

// 4. AST Traversal (pkg/sql/ast):

// visitor := &MyVisitor{}

// ast.Walk(visitor, astObj.Statements[0])

// # Supported SQL Dialects

// GoSQLX supports multiple SQL dialects through the keywords package:

// - PostgreSQL: Full support including LATERAL, RETURNING, ILIKE, MATERIALIZED

// - MySQL: ZEROFILL, UNSIGNED, FORCE, IGNORE

// - SQL Server: Dialect-specific keywords

// - Oracle: Dialect-specific keywords

// - SQLite: AUTOINCREMENT, VACUUM, ATTACH, DETACH

// - Generic: Standard SQL-99 keywords common to all dialects

// Example dialect usage:

// import "github.com/ajitpratap0/GoSQLX/pkg/sql/keywords"

// kw := keywords.New(keywords.DialectPostgreSQL, true)

// if kw.IsKeyword("LATERAL") {

// // Handle PostgreSQL-specific LATERAL keyword

// }

// # Advanced SQL Features (v1.6.0)

// The sql package supports comprehensive SQL-99 features:

// Window Functions (SQL-99 F611):

// SELECT name, salary,

// ROW_NUMBER() OVER (PARTITION BY dept ORDER BY salary DESC) as rank,

// LAG(salary, 1) OVER (ORDER BY hire_date) as prev_salary

// FROM employees

// Common Table Expressions (SQL-99 F121):

// WITH sales_summary AS (

// SELECT region, SUM(amount) as total FROM sales GROUP BY region

// )

// SELECT * FROM sales_summary WHERE total > 1000

// Recursive CTEs (SQL-99 F131):

// WITH RECURSIVE employee_tree AS (

// SELECT id, name, manager_id FROM employees WHERE manager_id IS NULL

// UNION ALL

// SELECT e.id, e.name, e.manager_id

// FROM employees e JOIN employee_tree et ON e.manager_id = et.id

// )

// SELECT * FROM employee_tree

// Set Operations (SQL-99 F302):

// SELECT name FROM customers

// UNION

// SELECT name FROM suppliers

// EXCEPT

// SELECT name FROM blacklist

// PostgreSQL Extensions (v1.6.0):

// -- LATERAL JOIN

// SELECT u.name, r.order_date FROM users u,

// LATERAL (SELECT * FROM orders WHERE user_id = u.id LIMIT 3) r

// -- DISTINCT ON

// SELECT DISTINCT ON (dept_id) dept_id, name, salary

// FROM employees ORDER BY dept_id, salary DESC

// -- JSON operators

// SELECT data->>'name', data->'address'->>'city' FROM users

// -- FILTER clause

// SELECT COUNT(*) FILTER (WHERE status = 'active') FROM users

// -- RETURNING clause

// INSERT INTO users (name) VALUES ('John') RETURNING id, created_at

// GROUPING SETS, ROLLUP, CUBE (SQL-99 T431):

// SELECT region, product, SUM(sales)

// FROM orders

// GROUP BY GROUPING SETS ((region), (product), ())

// SELECT year, quarter, SUM(revenue)

// FROM sales

// GROUP BY ROLLUP (year, quarter)

// SELECT region, product, SUM(amount)

// FROM sales

// GROUP BY CUBE (region, product)

// MERGE Statements (SQL:2003 F312):

// MERGE INTO target t USING source s ON t.id = s.id

// WHEN MATCHED THEN UPDATE SET t.value = s.value

// WHEN NOT MATCHED THEN INSERT (id, value) VALUES (s.id, s.value)

// Materialized Views:

// CREATE MATERIALIZED VIEW sales_summary AS

// SELECT region, SUM(amount) FROM sales GROUP BY region

// REFRESH MATERIALIZED VIEW CONCURRENTLY sales_summary

// # Performance Characteristics

// The sql package is optimized for high-performance parsing:

// - Zero-copy tokenization: Direct byte slice operations

// - Object pooling: 60-80% memory reduction via sync.Pool

// - Concurrent parsing: Thread-safe, scales linearly to 128+ cores

// - 1.38M+ ops/sec sustained throughput

// - 1.5M+ ops/sec peak throughput

// - 8M+ tokens/sec processing speed

// - <1μs latency for complex queries

// Memory management:

// // CORRECT: Always use defer with pool returns

// tkz := tokenizer.GetTokenizer()

// defer tokenizer.PutTokenizer(tkz)

// astObj := ast.NewAST()

// defer ast.ReleaseAST(astObj)

// # Thread Safety

// All sql subpackages are designed for concurrent use:

// - Tokenizers from pool are safe for single-goroutine use

// - Parsers are stateless and safe for concurrent creation

// - AST nodes are immutable after creation

// - Object pools use sync.Pool for thread-safe access

// - Keywords package is read-only after initialization

// Race detection validation:

// go test -race ./pkg/sql/...

// # Error Handling

// The sql package provides detailed error information:

// tokens, err := tkz.Tokenize(sqlBytes)

// if err != nil {

// // Error includes line, column, and context

// fmt.Printf("Tokenization error: %v\n", err)

// }

// astObj, err := parser.Parse(tokens)

// if err != nil {

// // Parser errors include token position and expected vs actual

// fmt.Printf("Parse error: %v\n", err)

// }

// # Security Scanning

// The sql/security subpackage provides SQL injection detection:

// import "github.com/ajitpratapsingh/GoSQLX/pkg/sql/security"

// scanner := security.NewScanner()

// findings := scanner.Scan(sqlBytes)

// for _, finding := range findings {

// fmt.Printf("Security issue: %s (severity: %s)\n",

// finding.Description, finding.Severity)

// }

// # SQL Compatibility

// SQL-99 compliance: ~80-85% of SQL-99 standard

// Fully supported:

// - Basic SELECT, INSERT, UPDATE, DELETE

// - All JOIN types (INNER, LEFT, RIGHT, FULL, CROSS, NATURAL)

// - Subqueries in SELECT, FROM, WHERE clauses

// - Window functions with PARTITION BY, ORDER BY, frame clauses

// - Common Table Expressions (CTEs) with WITH clause

// - Recursive CTEs with WITH RECURSIVE

// - Set operations (UNION, EXCEPT, INTERSECT) with ALL variants

// - Aggregate functions with GROUP BY, HAVING

// - ORDER BY with ASC/DESC, NULLS FIRST/LAST

// - CASE expressions (simple and searched)

// - BETWEEN, IN, LIKE, IS NULL operators

// - GROUPING SETS, ROLLUP, CUBE

// - MERGE statements

// - Materialized views

// Partially supported:

// - DDL statements (CREATE, ALTER, DROP)

// - Complex constraints

// - Stored procedures (syntax recognition only)

// Not yet supported:

// - Full SQL:2011 temporal features

// - Some advanced windowing features

// - Full OLAP extensions

// # Subpackage Details

// tokenizer:

// - Zero-copy lexical analysis

// - UTF-8/Unicode support

// - Position tracking (line, column)

// - Object pooling for tokenizer instances

// - Performance: 8M+ tokens/second

// parser:

// - Recursive descent parser

// - One-token lookahead

// - Comprehensive SQL-99 support

// - Error recovery and detailed messages

// - Object pooling for statements

// ast:

// - Complete node hierarchy

// - Visitor pattern support

// - Object pooling for all node types

// - Immutable after creation

// - 73.4% test coverage

// token:

// - Token type definitions

// - Token pool management

// - Comprehensive token categories

// keywords:

// - Multi-dialect keyword recognition

// - Compound keyword support (GROUP BY, ORDER BY, etc.)

// - Case-sensitive/insensitive modes

// - Categorized keywords (DML, DDL, functions, etc.)

// security:

// - SQL injection pattern detection

// - Severity classification (high, medium, low)

// - Zero false positives on valid parameterized queries

// # Example: Complete Parsing Pipeline

// package main

// import (

// "fmt"

// "log"

// "github.com/ajitpratap0/GoSQLX/pkg/sql/tokenizer"

// "github.com/ajitpratap0/GoSQLX/pkg/sql/parser"

// "github.com/ajitpratap0/GoSQLX/pkg/sql/ast"

// )

// func main() {

// sql := `WITH sales AS (

// SELECT region, SUM(amount) as total FROM orders GROUP BY region

// )

// SELECT * FROM sales WHERE total > 1000`

// // Tokenize

// tkz := tokenizer.GetTokenizer()

// defer tokenizer.PutTokenizer(tkz)

// tokens, err := tkz.Tokenize([]byte(sql))

// if err != nil {

// log.Fatal(err)

// }

// // Parse

// p := &parser.Parser{}

// astObj, err := p.Parse(tokens)

// if err != nil {

// log.Fatal(err)

// }

// defer ast.ReleaseAST(astObj)

// // Process AST

// fmt.Printf("Parsed %d statements\n", len(astObj.Statements))

// }

// # Version History

// v1.6.0: PostgreSQL extensions (LATERAL, JSON operators, DISTINCT ON, FILTER, RETURNING)

// v1.5.0: GROUPING SETS, ROLLUP, CUBE, MERGE statements, materialized views

// v1.4.0: Window functions with PARTITION BY, ORDER BY, frame clauses

// v1.3.0: Common Table Expressions (CTEs) and recursive CTEs

// v1.2.0: Set operations (UNION, EXCEPT, INTERSECT)

// v1.1.0: Complete JOIN support

// v1.0.0: Basic SQL parsing with SELECT, INSERT, UPDATE, DELETE

// # See Also

// - pkg/sql/tokenizer - Tokenization and lexical analysis

// - pkg/sql/parser - SQL parsing and AST generation

// - pkg/sql/ast - AST node definitions

// - pkg/sql/keywords - Keyword and dialect management

// - pkg/sql/security - Security scanning

// - docs/SQL_COMPATIBILITY.md - Detailed SQL compatibility matrix

// - docs/ARCHITECTURE.md - System architecture documentation

package sql

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