feat: ✨ Added Sqlite reader

pkg/readers/sqlite/README.md

@@ -0,0 +1,75 @@
+# SQLite Reader
+
+Reads database schema from SQLite database files.
+
+## Usage
+
+```go
+import (
+    "git.warky.dev/wdevs/relspecgo/pkg/readers"
+    "git.warky.dev/wdevs/relspecgo/pkg/readers/sqlite"
+)
+
+// Using file path
+options := &readers.ReaderOptions{
+    FilePath: "path/to/database.db",
+}
+
+reader := sqlite.NewReader(options)
+db, err := reader.ReadDatabase()
+
+// Or using connection string
+options := &readers.ReaderOptions{
+    ConnectionString: "path/to/database.db",
+}
+```
+
+## Features
+
+- Reads tables with columns and data types
+- Reads views with definitions
+- Reads primary keys
+- Reads foreign keys with CASCADE actions
+- Reads indexes (non-auto-generated)
+- Maps SQLite types to canonical types
+- Derives relationships from foreign keys
+
+## SQLite Specifics
+
+- SQLite doesn't support schemas, creates single "main" schema
+- Uses pure Go driver (modernc.org/sqlite) - no CGo required
+- Supports both file path and connection string
+- Auto-increment detection for INTEGER PRIMARY KEY columns
+- Foreign keys require `PRAGMA foreign_keys = ON` to be set
+
+## Example Schema
+
+```sql
+PRAGMA foreign_keys = ON;
+
+CREATE TABLE users (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    username VARCHAR(50) NOT NULL UNIQUE,
+    email VARCHAR(100) NOT NULL
+);
+
+CREATE TABLE posts (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL,
+    title VARCHAR(200) NOT NULL,
+    FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+);
+```
+
+## Type Mappings
+
+| SQLite Type | Canonical Type |
+|-------------|---------------|
+| INTEGER, INT | int |
+| BIGINT | int64 |
+| REAL, DOUBLE | float64 |
+| TEXT, VARCHAR | string |
+| BLOB | bytea |
+| BOOLEAN | bool |
+| DATE | date |
+| DATETIME, TIMESTAMP | timestamp |

pkg/readers/sqlite/queries.go

@@ -0,0 +1,306 @@
+package sqlite
+
+import (
+	"fmt"
+	"strings"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+)
+
+// queryTables retrieves all tables from the SQLite database
+func (r *Reader) queryTables() ([]*models.Table, error) {
+	query := `
+		SELECT name
+		FROM sqlite_master
+		WHERE type = 'table'
+		  AND name NOT LIKE 'sqlite_%'
+		ORDER BY name
+	`
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	tables := make([]*models.Table, 0)
+	for rows.Next() {
+		var tableName string
+
+		if err := rows.Scan(&tableName); err != nil {
+			return nil, err
+		}
+
+		table := models.InitTable(tableName, "main")
+		tables = append(tables, table)
+	}
+
+	return tables, rows.Err()
+}
+
+// queryViews retrieves all views from the SQLite database
+func (r *Reader) queryViews() ([]*models.View, error) {
+	query := `
+		SELECT name, sql
+		FROM sqlite_master
+		WHERE type = 'view'
+		ORDER BY name
+	`
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	views := make([]*models.View, 0)
+	for rows.Next() {
+		var viewName string
+		var sql *string
+
+		if err := rows.Scan(&viewName, &sql); err != nil {
+			return nil, err
+		}
+
+		view := models.InitView(viewName, "main")
+		if sql != nil {
+			view.Definition = *sql
+		}
+
+		views = append(views, view)
+	}
+
+	return views, rows.Err()
+}
+
+// queryColumns retrieves all columns for a given table or view
+func (r *Reader) queryColumns(tableName string) (map[string]*models.Column, error) {
+	query := fmt.Sprintf("PRAGMA table_info(%s)", tableName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	columns := make(map[string]*models.Column)
+
+	for rows.Next() {
+		var cid int
+		var name, dataType string
+		var notNull, pk int
+		var defaultValue *string
+
+		if err := rows.Scan(&cid, &name, &dataType, &notNull, &defaultValue, &pk); err != nil {
+			return nil, err
+		}
+
+		column := models.InitColumn(name, tableName, "main")
+		column.Type = r.mapDataType(strings.ToUpper(dataType))
+		column.NotNull = (notNull == 1)
+		column.IsPrimaryKey = (pk > 0)
+		column.Sequence = uint(cid + 1)
+
+		if defaultValue != nil {
+			column.Default = *defaultValue
+		}
+
+		// Check for autoincrement (SQLite uses INTEGER PRIMARY KEY AUTOINCREMENT)
+		if pk > 0 && strings.ToUpper(dataType) == "INTEGER" {
+			column.AutoIncrement = r.isAutoIncrement(tableName, name)
+		}
+
+		columns[name] = column
+	}
+
+	return columns, rows.Err()
+}
+
+// isAutoIncrement checks if a column is autoincrement
+func (r *Reader) isAutoIncrement(tableName, columnName string) bool {
+	// Check sqlite_sequence table or parse CREATE TABLE statement
+	query := `
+		SELECT sql
+		FROM sqlite_master
+		WHERE type = 'table' AND name = ?
+	`
+
+	var sql string
+	err := r.db.QueryRowContext(r.ctx, query, tableName).Scan(&sql)
+	if err != nil {
+		return false
+	}
+
+	// Check if the SQL contains AUTOINCREMENT for this column
+	return strings.Contains(strings.ToUpper(sql), strings.ToUpper(columnName)+" INTEGER PRIMARY KEY AUTOINCREMENT") ||
+		strings.Contains(strings.ToUpper(sql), strings.ToUpper(columnName)+" INTEGER AUTOINCREMENT")
+}
+
+// queryPrimaryKey retrieves the primary key constraint for a table
+func (r *Reader) queryPrimaryKey(tableName string) (*models.Constraint, error) {
+	query := fmt.Sprintf("PRAGMA table_info(%s)", tableName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var pkColumns []string
+
+	for rows.Next() {
+		var cid int
+		var name, dataType string
+		var notNull, pk int
+		var defaultValue *string
+
+		if err := rows.Scan(&cid, &name, &dataType, &notNull, &defaultValue, &pk); err != nil {
+			return nil, err
+		}
+
+		if pk > 0 {
+			pkColumns = append(pkColumns, name)
+		}
+	}
+
+	if len(pkColumns) == 0 {
+		return nil, nil
+	}
+
+	// Create primary key constraint
+	constraintName := fmt.Sprintf("%s_pkey", tableName)
+	constraint := models.InitConstraint(constraintName, models.PrimaryKeyConstraint)
+	constraint.Schema = "main"
+	constraint.Table = tableName
+	constraint.Columns = pkColumns
+
+	return constraint, rows.Err()
+}
+
+// queryForeignKeys retrieves all foreign key constraints for a table
+func (r *Reader) queryForeignKeys(tableName string) ([]*models.Constraint, error) {
+	query := fmt.Sprintf("PRAGMA foreign_key_list(%s)", tableName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	// Group foreign keys by id (since composite FKs have multiple rows)
+	fkMap := make(map[int]*models.Constraint)
+
+	for rows.Next() {
+		var id, seq int
+		var referencedTable, fromColumn, toColumn string
+		var onUpdate, onDelete, match string
+
+		if err := rows.Scan(&id, &seq, &referencedTable, &fromColumn, &toColumn, &onUpdate, &onDelete, &match); err != nil {
+			return nil, err
+		}
+
+		if _, exists := fkMap[id]; !exists {
+			constraintName := fmt.Sprintf("%s_%s_fkey", tableName, referencedTable)
+			if id > 0 {
+				constraintName = fmt.Sprintf("%s_%s_fkey_%d", tableName, referencedTable, id)
+			}
+
+			constraint := models.InitConstraint(constraintName, models.ForeignKeyConstraint)
+			constraint.Schema = "main"
+			constraint.Table = tableName
+			constraint.ReferencedSchema = "main"
+			constraint.ReferencedTable = referencedTable
+			constraint.OnUpdate = onUpdate
+			constraint.OnDelete = onDelete
+			constraint.Columns = []string{}
+			constraint.ReferencedColumns = []string{}
+
+			fkMap[id] = constraint
+		}
+
+		// Add column to the constraint
+		fkMap[id].Columns = append(fkMap[id].Columns, fromColumn)
+		fkMap[id].ReferencedColumns = append(fkMap[id].ReferencedColumns, toColumn)
+	}
+
+	// Convert map to slice
+	foreignKeys := make([]*models.Constraint, 0, len(fkMap))
+	for _, fk := range fkMap {
+		foreignKeys = append(foreignKeys, fk)
+	}
+
+	return foreignKeys, rows.Err()
+}
+
+// queryIndexes retrieves all indexes for a table
+func (r *Reader) queryIndexes(tableName string) ([]*models.Index, error) {
+	query := fmt.Sprintf("PRAGMA index_list(%s)", tableName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	indexes := make([]*models.Index, 0)
+
+	for rows.Next() {
+		var seq int
+		var name string
+		var unique int
+		var origin string
+		var partial int
+
+		if err := rows.Scan(&seq, &name, &unique, &origin, &partial); err != nil {
+			return nil, err
+		}
+
+		// Skip auto-generated indexes (origin = 'pk' for primary keys, etc.)
+		// origin: c = CREATE INDEX, u = UNIQUE constraint, pk = PRIMARY KEY
+		if origin == "pk" || origin == "u" {
+			continue
+		}
+
+		index := models.InitIndex(name, tableName, "main")
+		index.Unique = (unique == 1)
+
+		// Get index columns
+		columns, err := r.queryIndexColumns(name)
+		if err != nil {
+			return nil, err
+		}
+		index.Columns = columns
+
+		indexes = append(indexes, index)
+	}
+
+	return indexes, rows.Err()
+}
+
+// queryIndexColumns retrieves the columns for a specific index
+func (r *Reader) queryIndexColumns(indexName string) ([]string, error) {
+	query := fmt.Sprintf("PRAGMA index_info(%s)", indexName)
+
+	rows, err := r.db.QueryContext(r.ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	columns := make([]string, 0)
+
+	for rows.Next() {
+		var seqno, cid int
+		var name *string
+
+		if err := rows.Scan(&seqno, &cid, &name); err != nil {
+			return nil, err
+		}
+
+		if name != nil {
+			columns = append(columns, *name)
+		}
+	}
+
+	return columns, rows.Err()
+}

pkg/readers/sqlite/reader.go

@@ -0,0 +1,261 @@
+package sqlite
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"path/filepath"
+
+	_ "modernc.org/sqlite" // SQLite driver
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+)
+
+// Reader implements the readers.Reader interface for SQLite databases
+type Reader struct {
+	options *readers.ReaderOptions
+	db      *sql.DB
+	ctx     context.Context
+}
+
+// NewReader creates a new SQLite reader
+func NewReader(options *readers.ReaderOptions) *Reader {
+	return &Reader{
+		options: options,
+		ctx:     context.Background(),
+	}
+}
+
+// ReadDatabase reads the entire database schema from SQLite
+func (r *Reader) ReadDatabase() (*models.Database, error) {
+	// Validate file path or connection string
+	dbPath := r.options.FilePath
+	if dbPath == "" && r.options.ConnectionString != "" {
+		dbPath = r.options.ConnectionString
+	}
+	if dbPath == "" {
+		return nil, fmt.Errorf("file path or connection string is required")
+	}
+
+	// Connect to the database
+	if err := r.connect(dbPath); err != nil {
+		return nil, fmt.Errorf("failed to connect: %w", err)
+	}
+	defer r.close()
+
+	// Get database name from file path
+	dbName := filepath.Base(dbPath)
+	if dbName == "" {
+		dbName = "sqlite"
+	}
+
+	// Initialize database model
+	db := models.InitDatabase(dbName)
+	db.DatabaseType = models.SqlLiteDatabaseType
+	db.SourceFormat = "sqlite"
+
+	// Get SQLite version
+	var version string
+	err := r.db.QueryRowContext(r.ctx, "SELECT sqlite_version()").Scan(&version)
+	if err == nil {
+		db.DatabaseVersion = version
+	}
+
+	// SQLite doesn't have schemas, so we create a single "main" schema
+	schema := models.InitSchema("main")
+	schema.RefDatabase = db
+
+	// Query tables
+	tables, err := r.queryTables()
+	if err != nil {
+		return nil, fmt.Errorf("failed to query tables: %w", err)
+	}
+	schema.Tables = tables
+
+	// Query views
+	views, err := r.queryViews()
+	if err != nil {
+		return nil, fmt.Errorf("failed to query views: %w", err)
+	}
+	schema.Views = views
+
+	// Query columns for tables and views
+	for _, table := range schema.Tables {
+		columns, err := r.queryColumns(table.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query columns for table %s: %w", table.Name, err)
+		}
+		table.Columns = columns
+		table.RefSchema = schema
+
+		// Query primary key
+		pk, err := r.queryPrimaryKey(table.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query primary key for table %s: %w", table.Name, err)
+		}
+		if pk != nil {
+			table.Constraints[pk.Name] = pk
+			// Mark columns as primary key and not null
+			for _, colName := range pk.Columns {
+				if col, exists := table.Columns[colName]; exists {
+					col.IsPrimaryKey = true
+					col.NotNull = true
+				}
+			}
+		}
+
+		// Query foreign keys
+		foreignKeys, err := r.queryForeignKeys(table.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query foreign keys for table %s: %w", table.Name, err)
+		}
+		for _, fk := range foreignKeys {
+			table.Constraints[fk.Name] = fk
+			// Derive relationship from foreign key
+			r.deriveRelationship(table, fk)
+		}
+
+		// Query indexes
+		indexes, err := r.queryIndexes(table.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query indexes for table %s: %w", table.Name, err)
+		}
+		for _, idx := range indexes {
+			table.Indexes[idx.Name] = idx
+		}
+	}
+
+	// Query columns for views
+	for _, view := range schema.Views {
+		columns, err := r.queryColumns(view.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to query columns for view %s: %w", view.Name, err)
+		}
+		view.Columns = columns
+		view.RefSchema = schema
+	}
+
+	// Add schema to database
+	db.Schemas = append(db.Schemas, schema)
+
+	return db, nil
+}
+
+// ReadSchema reads a single schema (returns the main schema from the database)
+func (r *Reader) ReadSchema() (*models.Schema, error) {
+	db, err := r.ReadDatabase()
+	if err != nil {
+		return nil, err
+	}
+	if len(db.Schemas) == 0 {
+		return nil, fmt.Errorf("no schemas found in database")
+	}
+	return db.Schemas[0], nil
+}
+
+// ReadTable reads a single table (returns the first table from the schema)
+func (r *Reader) ReadTable() (*models.Table, error) {
+	schema, err := r.ReadSchema()
+	if err != nil {
+		return nil, err
+	}
+	if len(schema.Tables) == 0 {
+		return nil, fmt.Errorf("no tables found in schema")
+	}
+	return schema.Tables[0], nil
+}
+
+// connect establishes a connection to the SQLite database
+func (r *Reader) connect(dbPath string) error {
+	db, err := sql.Open("sqlite", dbPath)
+	if err != nil {
+		return err
+	}
+	r.db = db
+	return nil
+}
+
+// close closes the database connection
+func (r *Reader) close() {
+	if r.db != nil {
+		r.db.Close()
+	}
+}
+
+// mapDataType maps SQLite data types to canonical types
+func (r *Reader) mapDataType(sqliteType string) string {
+	// SQLite has a flexible type system, but we map common types
+	typeMap := map[string]string{
+		"INTEGER":  "int",
+		"INT":      "int",
+		"TINYINT":  "int8",
+		"SMALLINT": "int16",
+		"MEDIUMINT": "int",
+		"BIGINT":   "int64",
+		"UNSIGNED BIG INT": "uint64",
+		"INT2":     "int16",
+		"INT8":     "int64",
+		"REAL":     "float64",
+		"DOUBLE":   "float64",
+		"DOUBLE PRECISION": "float64",
+		"FLOAT":    "float32",
+		"NUMERIC":  "decimal",
+		"DECIMAL":  "decimal",
+		"BOOLEAN":  "bool",
+		"BOOL":     "bool",
+		"DATE":     "date",
+		"DATETIME": "timestamp",
+		"TIMESTAMP": "timestamp",
+		"TEXT":     "string",
+		"VARCHAR":  "string",
+		"CHAR":     "string",
+		"CHARACTER": "string",
+		"VARYING CHARACTER": "string",
+		"NCHAR":    "string",
+		"NVARCHAR": "string",
+		"CLOB":     "text",
+		"BLOB":     "bytea",
+	}
+
+	// Try exact match first
+	if mapped, exists := typeMap[sqliteType]; exists {
+		return mapped
+	}
+
+	// Try case-insensitive match for common types
+	sqliteTypeUpper := sqliteType
+	if len(sqliteType) > 0 {
+		// Extract base type (e.g., "VARCHAR(255)" -> "VARCHAR")
+		for baseType := range typeMap {
+			if len(sqliteTypeUpper) >= len(baseType) && sqliteTypeUpper[:len(baseType)] == baseType {
+				return typeMap[baseType]
+			}
+		}
+	}
+
+	// Default to string for unknown types
+	return "string"
+}
+
+// deriveRelationship creates a relationship from a foreign key constraint
+func (r *Reader) deriveRelationship(table *models.Table, fk *models.Constraint) {
+	relationshipName := fmt.Sprintf("%s_to_%s", table.Name, fk.ReferencedTable)
+
+	relationship := models.InitRelationship(relationshipName, models.OneToMany)
+	relationship.FromTable = table.Name
+	relationship.FromSchema = table.Schema
+	relationship.ToTable = fk.ReferencedTable
+	relationship.ToSchema = fk.ReferencedSchema
+	relationship.ForeignKey = fk.Name
+
+	// Store constraint actions in properties
+	if fk.OnDelete != "" {
+		relationship.Properties["on_delete"] = fk.OnDelete
+	}
+	if fk.OnUpdate != "" {
+		relationship.Properties["on_update"] = fk.OnUpdate
+	}
+
+	table.Relationships[relationshipName] = relationship
+}

pkg/readers/sqlite/reader_test.go

@@ -0,0 +1,334 @@
+package sqlite
+
+import (
+	"database/sql"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"git.warky.dev/wdevs/relspecgo/pkg/models"
+	"git.warky.dev/wdevs/relspecgo/pkg/readers"
+)
+
+// setupTestDatabase creates a temporary SQLite database with test data
+func setupTestDatabase(t *testing.T) string {
+	tmpDir := t.TempDir()
+	dbPath := filepath.Join(tmpDir, "test.db")
+
+	db, err := sql.Open("sqlite", dbPath)
+	require.NoError(t, err)
+	defer db.Close()
+
+	// Create test schema
+	schema := `
+		PRAGMA foreign_keys = ON;
+
+		CREATE TABLE users (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			username VARCHAR(50) NOT NULL UNIQUE,
+			email VARCHAR(100) NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+		);
+
+		CREATE TABLE posts (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			user_id INTEGER NOT NULL,
+			title VARCHAR(200) NOT NULL,
+			content TEXT,
+			published BOOLEAN DEFAULT 0,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+		);
+
+		CREATE TABLE comments (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			post_id INTEGER NOT NULL,
+			user_id INTEGER NOT NULL,
+			comment TEXT NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (post_id) REFERENCES posts(id) ON DELETE CASCADE,
+			FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+		);
+
+		CREATE INDEX idx_posts_user_id ON posts(user_id);
+		CREATE INDEX idx_comments_post_id ON comments(post_id);
+		CREATE UNIQUE INDEX idx_users_email ON users(email);
+
+		CREATE VIEW user_post_count AS
+		SELECT u.id, u.username, COUNT(p.id) as post_count
+		FROM users u
+		LEFT JOIN posts p ON u.id = p.user_id
+		GROUP BY u.id, u.username;
+	`
+
+	_, err = db.Exec(schema)
+	require.NoError(t, err)
+
+	return dbPath
+}
+
+func TestReader_ReadDatabase(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	// Check database metadata
+	assert.Equal(t, "test.db", db.Name)
+	assert.Equal(t, models.SqlLiteDatabaseType, db.DatabaseType)
+	assert.Equal(t, "sqlite", db.SourceFormat)
+	assert.NotEmpty(t, db.DatabaseVersion)
+
+	// Check schemas (SQLite should have a single "main" schema)
+	require.Len(t, db.Schemas, 1)
+	schema := db.Schemas[0]
+	assert.Equal(t, "main", schema.Name)
+
+	// Check tables
+	assert.Len(t, schema.Tables, 3)
+	tableNames := make([]string, len(schema.Tables))
+	for i, table := range schema.Tables {
+		tableNames[i] = table.Name
+	}
+	assert.Contains(t, tableNames, "users")
+	assert.Contains(t, tableNames, "posts")
+	assert.Contains(t, tableNames, "comments")
+
+	// Check views
+	assert.Len(t, schema.Views, 1)
+	assert.Equal(t, "user_post_count", schema.Views[0].Name)
+	assert.NotEmpty(t, schema.Views[0].Definition)
+}
+
+func TestReader_ReadTable_Users(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	// Find users table
+	var usersTable *models.Table
+	for _, table := range db.Schemas[0].Tables {
+		if table.Name == "users" {
+			usersTable = table
+			break
+		}
+	}
+
+	require.NotNil(t, usersTable)
+	assert.Equal(t, "users", usersTable.Name)
+	assert.Equal(t, "main", usersTable.Schema)
+
+	// Check columns
+	assert.Len(t, usersTable.Columns, 4)
+
+	// Check id column
+	idCol, exists := usersTable.Columns["id"]
+	require.True(t, exists)
+	assert.Equal(t, "int", idCol.Type)
+	assert.True(t, idCol.IsPrimaryKey)
+	assert.True(t, idCol.AutoIncrement)
+	assert.True(t, idCol.NotNull)
+
+	// Check username column
+	usernameCol, exists := usersTable.Columns["username"]
+	require.True(t, exists)
+	assert.Equal(t, "string", usernameCol.Type)
+	assert.True(t, usernameCol.NotNull)
+	assert.False(t, usernameCol.IsPrimaryKey)
+
+	// Check email column
+	emailCol, exists := usersTable.Columns["email"]
+	require.True(t, exists)
+	assert.Equal(t, "string", emailCol.Type)
+	assert.True(t, emailCol.NotNull)
+
+	// Check primary key constraint
+	assert.Len(t, usersTable.Constraints, 1)
+	pkConstraint, exists := usersTable.Constraints["users_pkey"]
+	require.True(t, exists)
+	assert.Equal(t, models.PrimaryKeyConstraint, pkConstraint.Type)
+	assert.Equal(t, []string{"id"}, pkConstraint.Columns)
+
+	// Check indexes (should have unique index on email and username)
+	assert.GreaterOrEqual(t, len(usersTable.Indexes), 1)
+}
+
+func TestReader_ReadTable_Posts(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	// Find posts table
+	var postsTable *models.Table
+	for _, table := range db.Schemas[0].Tables {
+		if table.Name == "posts" {
+			postsTable = table
+			break
+		}
+	}
+
+	require.NotNil(t, postsTable)
+
+	// Check columns
+	assert.Len(t, postsTable.Columns, 6)
+
+	// Check foreign key constraint
+	hasForeignKey := false
+	for _, constraint := range postsTable.Constraints {
+		if constraint.Type == models.ForeignKeyConstraint {
+			hasForeignKey = true
+			assert.Equal(t, "users", constraint.ReferencedTable)
+			assert.Equal(t, "CASCADE", constraint.OnDelete)
+		}
+	}
+	assert.True(t, hasForeignKey, "Posts table should have a foreign key constraint")
+
+	// Check relationships
+	assert.GreaterOrEqual(t, len(postsTable.Relationships), 1)
+
+	// Check indexes
+	hasUserIdIndex := false
+	for _, index := range postsTable.Indexes {
+		if index.Name == "idx_posts_user_id" {
+			hasUserIdIndex = true
+			assert.Contains(t, index.Columns, "user_id")
+		}
+	}
+	assert.True(t, hasUserIdIndex, "Posts table should have idx_posts_user_id index")
+}
+
+func TestReader_ReadTable_Comments(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+
+	// Find comments table
+	var commentsTable *models.Table
+	for _, table := range db.Schemas[0].Tables {
+		if table.Name == "comments" {
+			commentsTable = table
+			break
+		}
+	}
+
+	require.NotNil(t, commentsTable)
+
+	// Check foreign key constraints (should have 2)
+	fkCount := 0
+	for _, constraint := range commentsTable.Constraints {
+		if constraint.Type == models.ForeignKeyConstraint {
+			fkCount++
+		}
+	}
+	assert.Equal(t, 2, fkCount, "Comments table should have 2 foreign key constraints")
+}
+
+func TestReader_ReadSchema(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	schema, err := reader.ReadSchema()
+
+	require.NoError(t, err)
+	require.NotNil(t, schema)
+	assert.Equal(t, "main", schema.Name)
+	assert.Len(t, schema.Tables, 3)
+	assert.Len(t, schema.Views, 1)
+}
+
+func TestReader_ReadTable(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		FilePath: dbPath,
+	}
+
+	reader := NewReader(options)
+	table, err := reader.ReadTable()
+
+	require.NoError(t, err)
+	require.NotNil(t, table)
+	assert.NotEmpty(t, table.Name)
+	assert.NotEmpty(t, table.Columns)
+}
+
+func TestReader_ConnectionString(t *testing.T) {
+	dbPath := setupTestDatabase(t)
+	defer os.Remove(dbPath)
+
+	options := &readers.ReaderOptions{
+		ConnectionString: dbPath,
+	}
+
+	reader := NewReader(options)
+	db, err := reader.ReadDatabase()
+
+	require.NoError(t, err)
+	require.NotNil(t, db)
+	assert.Len(t, db.Schemas, 1)
+}
+
+func TestReader_InvalidPath(t *testing.T) {
+	options := &readers.ReaderOptions{
+		FilePath: "/nonexistent/path/to/database.db",
+	}
+
+	reader := NewReader(options)
+	_, err := reader.ReadDatabase()
+
+	assert.Error(t, err)
+}
+
+func TestReader_MissingPath(t *testing.T) {
+	options := &readers.ReaderOptions{}
+
+	reader := NewReader(options)
+	_, err := reader.ReadDatabase()
+
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "file path or connection string is required")
+}