Added row PgSQLAdapter

pkg/common/adapters/database/pgsql_example.go

@@ -0,0 +1,176 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	_ "github.com/jackc/pgx/v5/stdlib" // PostgreSQL driver
+
+	"github.com/bitechdev/ResolveSpec/pkg/common"
+)
+
+// Example demonstrates how to use the PgSQL adapter
+func ExamplePgSQLAdapter() error {
+	// Connect to PostgreSQL database
+	dsn := "postgres://username:password@localhost:5432/dbname?sslmode=disable"
+	db, err := sql.Open("pgx", dsn)
+	if err != nil {
+		return fmt.Errorf("failed to open database: %w", err)
+	}
+	defer db.Close()
+
+	// Create the PgSQL adapter
+	adapter := NewPgSQLAdapter(db)
+
+	// Enable query debugging (optional)
+	adapter.EnableQueryDebug()
+
+	ctx := context.Background()
+
+	// Example 1: Simple SELECT query
+	var results []map[string]interface{}
+	err = adapter.NewSelect().
+		Table("users").
+		Where("age > ?", 18).
+		Order("created_at DESC").
+		Limit(10).
+		Scan(ctx, &results)
+	if err != nil {
+		return fmt.Errorf("select failed: %w", err)
+	}
+
+	// Example 2: INSERT query
+	result, err := adapter.NewInsert().
+		Table("users").
+		Value("name", "John Doe").
+		Value("email", "john@example.com").
+		Value("age", 25).
+		Returning("id").
+		Exec(ctx)
+	if err != nil {
+		return fmt.Errorf("insert failed: %w", err)
+	}
+	fmt.Printf("Rows affected: %d\n", result.RowsAffected())
+
+	// Example 3: UPDATE query
+	result, err = adapter.NewUpdate().
+		Table("users").
+		Set("name", "Jane Doe").
+		Where("id = ?", 1).
+		Exec(ctx)
+	if err != nil {
+		return fmt.Errorf("update failed: %w", err)
+	}
+	fmt.Printf("Rows updated: %d\n", result.RowsAffected())
+
+	// Example 4: DELETE query
+	result, err = adapter.NewDelete().
+		Table("users").
+		Where("age < ?", 18).
+		Exec(ctx)
+	if err != nil {
+		return fmt.Errorf("delete failed: %w", err)
+	}
+	fmt.Printf("Rows deleted: %d\n", result.RowsAffected())
+
+	// Example 5: Using transactions
+	err = adapter.RunInTransaction(ctx, func(tx common.Database) error {
+		// Insert a new user
+		_, err := tx.NewInsert().
+			Table("users").
+			Value("name", "Transaction User").
+			Value("email", "tx@example.com").
+			Exec(ctx)
+		if err != nil {
+			return err
+		}
+
+		// Update another user
+		_, err = tx.NewUpdate().
+			Table("users").
+			Set("verified", true).
+			Where("email = ?", "tx@example.com").
+			Exec(ctx)
+		if err != nil {
+			return err
+		}
+
+		// Both operations succeed or both rollback
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("transaction failed: %w", err)
+	}
+
+	// Example 6: JOIN query
+	err = adapter.NewSelect().
+		Table("users u").
+		Column("u.id", "u.name", "p.title as post_title").
+		LeftJoin("posts p ON p.user_id = u.id").
+		Where("u.active = ?", true).
+		Scan(ctx, &results)
+	if err != nil {
+		return fmt.Errorf("join query failed: %w", err)
+	}
+
+	// Example 7: Aggregation query
+	count, err := adapter.NewSelect().
+		Table("users").
+		Where("active = ?", true).
+		Count(ctx)
+	if err != nil {
+		return fmt.Errorf("count failed: %w", err)
+	}
+	fmt.Printf("Active users: %d\n", count)
+
+	// Example 8: Raw SQL execution
+	_, err = adapter.Exec(ctx, "CREATE INDEX IF NOT EXISTS idx_users_email ON users(email)")
+	if err != nil {
+		return fmt.Errorf("raw exec failed: %w", err)
+	}
+
+	// Example 9: Raw SQL query
+	var users []map[string]interface{}
+	err = adapter.Query(ctx, &users, "SELECT * FROM users WHERE age > $1 LIMIT $2", 18, 10)
+	if err != nil {
+		return fmt.Errorf("raw query failed: %w", err)
+	}
+
+	return nil
+}
+
+// User is an example model
+type User struct {
+	ID    int    `json:"id"`
+	Name  string `json:"name"`
+	Email string `json:"email"`
+	Age   int    `json:"age"`
+}
+
+// TableName implements common.TableNameProvider
+func (u User) TableName() string {
+	return "users"
+}
+
+// ExampleWithModel demonstrates using models with the PgSQL adapter
+func ExampleWithModel() error {
+	dsn := "postgres://username:password@localhost:5432/dbname?sslmode=disable"
+	db, err := sql.Open("pgx", dsn)
+	if err != nil {
+		return err
+	}
+	defer db.Close()
+
+	adapter := NewPgSQLAdapter(db)
+	ctx := context.Background()
+
+	// Use model with adapter
+	user := User{}
+	err = adapter.NewSelect().
+		Model(&user).
+		Where("id = ?", 1).
+		Scan(ctx, &user)
+
+	return err
+}