diff --git a/cmd/go_migrate/batch-generator.go b/cmd/go_migrate/batch-generator.go
index 2732b54..90791e9 100644
--- a/cmd/go_migrate/batch-generator.go
+++ b/cmd/go_migrate/batch-generator.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
 	"github.com/google/uuid"
 )
 
@@ -42,7 +43,7 @@ GROUP BY t.name`
 	return rowsCount, nil
 }
 
-func calculateBatchesMssql(ctx context.Context, db *sql.DB, tableInfo config.SourceTableInfo, batchCount int64) ([]Batch, error) {
+func calculateBatchesMssql(ctx context.Context, db *sql.DB, tableInfo config.SourceTableInfo, batchCount int64) ([]models.Batch, error) {
 	query := fmt.Sprintf(`
 SELECT
 	MIN([%s]) AS lower_limit,
@@ -67,10 +68,10 @@ ORDER BY batch_id`,
 	}
 	defer rows.Close()
 
-	batches := make([]Batch, 0, batchCount)
+	batches := make([]models.Batch, 0, batchCount)
 
 	for rows.Next() {
-		batch := Batch{
+		batch := models.Batch{
 			Id:                    uuid.New(),
 			ShouldUseRange:        true,
 			RetryCounter:          0,
@@ -91,7 +92,7 @@ ORDER BY batch_id`,
 	return batches, nil
 }
 
-func batchGeneratorMssql(ctx context.Context, db *sql.DB, tableInfo config.SourceTableInfo, rowsPerBatch int64) ([]Batch, error) {
+func batchGeneratorMssql(ctx context.Context, db *sql.DB, tableInfo config.SourceTableInfo, rowsPerBatch int64) ([]models.Batch, error) {
 	rowsCount, err := estimateTotalRowsMssql(ctx, db, tableInfo)
 	if err != nil {
 		return nil, err
@@ -101,7 +102,7 @@ func batchGeneratorMssql(ctx context.Context, db *sql.DB, tableInfo config.Sourc
 	if rowsCount > rowsPerBatch {
 		batchCount = rowsCount / rowsPerBatch
 	} else {
-		return []Batch{{
+		return []models.Batch{{
 			Id:             uuid.New(),
 			ShouldUseRange: false,
 			RetryCounter:   0,
diff --git a/cmd/go_migrate/inspect-columns.go b/cmd/go_migrate/inspect-columns.go
index e6936c4..6da878c 100644
--- a/cmd/go_migrate/inspect-columns.go
+++ b/cmd/go_migrate/inspect-columns.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
 	"github.com/jackc/pgx/v5/pgxpool"
 	_ "github.com/microsoft/go-mssqldb"
 	log "github.com/sirupsen/logrus"
@@ -67,7 +68,7 @@ func GetUnifiedType(systemType string) string {
 	return strings.ToUpper(systemType)
 }
 
-func MapPostgresColumn(column ColumnType, maxLength *int64, precision *int64, scale *int64) ColumnType {
+func MapPostgresColumn(column ColumnType, maxLength *int64, precision *int64, scale *int64) models.ColumnType {
 	stringTypes := map[string]bool{
 		"varchar": true, "char": true, "character": true, "text": true, "character varying": true,
 	}
@@ -109,10 +110,23 @@ func MapPostgresColumn(column ColumnType, maxLength *int64, precision *int64, sc
 
 	column.unifiedType = GetUnifiedType(column.systemType)
 
-	return column
+	colType := models.NewColumnType(
+		column.name,
+		column.hasMaxLength,
+		column.hasPrecisionScale,
+		column.userType,
+		column.systemType,
+		column.unifiedType,
+		column.nullable,
+		column.maxLength,
+		column.precision,
+		column.scale,
+	)
+
+	return colType
 }
 
-func GetColumnTypesPostgres(db *pgxpool.Pool, tableInfo config.TargetTableInfo) ([]ColumnType, error) {
+func GetColumnTypesPostgres(db *pgxpool.Pool, tableInfo config.TargetTableInfo) ([]models.ColumnType, error) {
 	query := `
 SELECT 
   c.column_name AS name,
@@ -136,7 +150,7 @@ ORDER BY c.ordinal_position;
 	}
 	defer rows.Close()
 
-	var colTypes []ColumnType
+	var colTypes []models.ColumnType
 
 	for rows.Next() {
 		var column ColumnType
@@ -162,7 +176,7 @@ ORDER BY c.ordinal_position;
 	return colTypes, nil
 }
 
-func MapMssqlColumn(column ColumnType) ColumnType {
+func MapMssqlColumn(column ColumnType) models.ColumnType {
 	stringTypes := map[string]bool{
 		"varchar": true, "char": true, "nvarchar": true, "nchar": true, "text": true, "ntext": true,
 	}
@@ -195,10 +209,23 @@ func MapMssqlColumn(column ColumnType) ColumnType {
 
 	column.unifiedType = GetUnifiedType(column.systemType)
 
-	return column
+	colType := models.NewColumnType(
+		column.name,
+		column.hasMaxLength,
+		column.hasPrecisionScale,
+		column.userType,
+		column.systemType,
+		column.unifiedType,
+		column.nullable,
+		column.maxLength,
+		column.precision,
+		column.scale,
+	)
+
+	return colType
 }
 
-func GetColumnTypesMssql(db *sql.DB, tableInfo config.SourceTableInfo) ([]ColumnType, error) {
+func GetColumnTypesMssql(db *sql.DB, tableInfo config.SourceTableInfo) ([]models.ColumnType, error) {
 	query := `
 SELECT 
 	c.name AS name,
@@ -226,7 +253,7 @@ ORDER BY c.column_id;
 	}
 	defer rows.Close()
 
-	var colTypes []ColumnType
+	var colTypes []models.ColumnType
 
 	for rows.Next() {
 		var column ColumnType
@@ -258,11 +285,11 @@ func GetColumnTypes(
 	targetDb *pgxpool.Pool,
 	sourceTable config.SourceTableInfo,
 	targetTable config.TargetTableInfo,
-) ([]ColumnType, []ColumnType, error) {
+) ([]models.ColumnType, []models.ColumnType, error) {
 	var sourceDbErr error
 	var targetDbErr error
-	var sourceColTypes []ColumnType
-	var targetColTypes []ColumnType
+	var sourceColTypes []models.ColumnType
+	var targetColTypes []models.ColumnType
 	var wg sync.WaitGroup
 
 	wg.Go(func() {
diff --git a/cmd/go_migrate/loader-error-handler.go b/cmd/go_migrate/loader-error-handler.go
index 205fa73..bb40a4c 100644
--- a/cmd/go_migrate/loader-error-handler.go
+++ b/cmd/go_migrate/loader-error-handler.go
@@ -4,10 +4,13 @@ import (
 	"context"
 	"fmt"
 	"sync"
+
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/custom_errors"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
 )
 
 type LoaderError struct {
-	Chunk
+	models.Chunk
 	Msg string
 }
 
@@ -18,8 +21,8 @@ func (e *LoaderError) Error() string {
 func loaderErrorHandler(
 	ctx context.Context,
 	chErrorsIn <-chan LoaderError,
-	chChunksOut chan<- Chunk,
-	chJobErrorsOut chan<- JobError,
+	chChunksOut chan<- models.Chunk,
+	chJobErrorsOut chan<- custom_errors.JobError,
 	wgActiveChunks *sync.WaitGroup,
 ) {
 	for {
@@ -37,7 +40,7 @@ func loaderErrorHandler(
 			}
 
 			if err.RetryCounter >= maxRetryAttempts {
-				jobError := JobError{
+				jobError := custom_errors.JobError{
 					ShouldCancelJob: false,
 					Msg:             fmt.Sprintf("chunk %v reached max retries (%d)", err.Id, maxRetryAttempts),
 					Prev:            &err,
diff --git a/cmd/go_migrate/loader.go b/cmd/go_migrate/loader.go
index 42e56af..1ded1fe 100644
--- a/cmd/go_migrate/loader.go
+++ b/cmd/go_migrate/loader.go
@@ -10,6 +10,8 @@ import (
 	"time"
 
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/custom_errors"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgconn"
 	"github.com/jackc/pgx/v5/pgxpool"
@@ -21,16 +23,16 @@ func loadRowsPostgres(
 	ctx context.Context,
 	db *pgxpool.Pool,
 	tableInfo config.TargetTableInfo,
-	columns []ColumnType,
-	chChunksIn <-chan Chunk,
+	columns []models.ColumnType,
+	chChunksIn <-chan models.Chunk,
 	chErrorsOut chan<- LoaderError,
-	chJobErrorsOut chan<- JobError,
+	chJobErrorsOut chan<- custom_errors.JobError,
 	wgActiveChunks *sync.WaitGroup,
 	rowsLoaded *int64,
 ) {
 	tableId := pgx.Identifier{tableInfo.Schema, tableInfo.Table}
-	colNames := Map(columns, func(col ColumnType) string {
-		return col.name
+	colNames := Map(columns, func(col models.ColumnType) string {
+		return col.Name()
 	})
 
 	for {
@@ -58,9 +60,9 @@ func loadChunkPostgres(
 	db *pgxpool.Pool,
 	identifier pgx.Identifier,
 	colNames []string,
-	chunk Chunk,
+	chunk models.Chunk,
 	chErrorsOut chan<- LoaderError,
-	chJobErrorsOut chan<- JobError,
+	chJobErrorsOut chan<- custom_errors.JobError,
 	wgActiveChunks *sync.WaitGroup,
 	rowsLoaded *int64,
 ) (abort bool) {
@@ -77,7 +79,7 @@ func loadChunkPostgres(
 		if errors.As(err, &pgErr) {
 			if pgErr.Code == "23505" {
 				select {
-				case chJobErrorsOut <- JobError{
+				case chJobErrorsOut <- custom_errors.JobError{
 					ShouldCancelJob: true,
 					Msg:             fmt.Sprintf("Fatal error in table %s", identifier.Sanitize()),
 					Prev:            err,
diff --git a/cmd/go_migrate/process.go b/cmd/go_migrate/process.go
index e274e4d..bb32c0f 100644
--- a/cmd/go_migrate/process.go
+++ b/cmd/go_migrate/process.go
@@ -8,6 +8,9 @@ import (
 	"time"
 
 	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/custom_errors"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/etl/extractor"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
 	"github.com/jackc/pgx/v5/pgxpool"
 
 	_ "github.com/microsoft/go-mssqldb"
@@ -44,11 +47,11 @@ func processMigrationJob(
 		log.Error("Unexpected error calculating batch ranges: ", err)
 	}
 
-	chJobErrors := make(chan JobError, job.QueueSize)
-	chBatches := make(chan Batch, job.QueueSize)
-	chExtractorErrors := make(chan ExtractorError, job.QueueSize)
-	chChunksRaw := make(chan Chunk, job.QueueSize)
-	chChunksTransformed := make(chan Chunk, job.QueueSize)
+	chJobErrors := make(chan custom_errors.JobError, job.QueueSize)
+	chBatches := make(chan models.Batch, job.QueueSize)
+	chExtractorErrors := make(chan custom_errors.ExtractorError, job.QueueSize)
+	chChunksRaw := make(chan models.Chunk, job.QueueSize)
+	chChunksTransformed := make(chan models.Chunk, job.QueueSize)
 	chLoadersErrors := make(chan LoaderError, job.QueueSize)
 
 	var wgActiveBatches sync.WaitGroup
@@ -58,21 +61,34 @@ func processMigrationJob(
 	var wgLoaders sync.WaitGroup
 
 	go func() {
-		if err := jobErrorHandler(jobCtx, chJobErrors); err != nil {
+		if err := custom_errors.JobErrorHandler(jobCtx, chJobErrors); err != nil {
 			cancel()
 			result.Error = err
 		}
 	}()
 
-	go extractorErrorHandler(jobCtx, chExtractorErrors, chBatches, chJobErrors, &wgActiveBatches)
+	go custom_errors.ExtractorErrorHandler(jobCtx, chExtractorErrors, chBatches, chJobErrors, &wgActiveBatches)
 	go loaderErrorHandler(jobCtx, chLoadersErrors, chChunksTransformed, chJobErrors, &wgActiveChunks)
 
 	maxExtractors := min(job.MaxExtractors, len(batches))
 	log.Infof("Starting %d extractor(s)...", maxExtractors)
 
+	exMssql := extractor.NewMssqlExtractor(sourceDb)
+
 	for range maxExtractors {
 		wgExtractors.Go(func() {
-			extractFromMssql(jobCtx, sourceDb, job.SourceTable, sourceColTypes, job.ChunkSize, chBatches, chChunksRaw, chExtractorErrors, chJobErrors, &wgActiveBatches, &rowsRead)
+			exMssql.Exec(
+				jobCtx,
+				job.SourceTable,
+				sourceColTypes,
+				job.ChunkSize,
+				chBatches,
+				chChunksRaw,
+				chExtractorErrors,
+				chJobErrors,
+				&wgActiveBatches,
+				&rowsRead,
+			)
 		})
 	}
 
@@ -132,7 +148,7 @@ func processMigrationJob(
 	return result
 }
 
-func logColumnTypes(columnTypes []ColumnType, label string) {
+func logColumnTypes(columnTypes []models.ColumnType, label string) {
 	log.Debug(label)
 
 	for _, col := range columnTypes {
diff --git a/cmd/go_migrate/transformer.go b/cmd/go_migrate/transformer.go
index 4107a0c..2ceba6f 100644
--- a/cmd/go_migrate/transformer.go
+++ b/cmd/go_migrate/transformer.go
@@ -6,6 +6,8 @@ import (
 	"sync"
 	"time"
 
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/custom_errors"
+	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/models"
 	log "github.com/sirupsen/logrus"
 )
 
@@ -18,10 +20,10 @@ type columnTransformPlan struct {
 
 func transformRowsMssql(
 	ctx context.Context,
-	columns []ColumnType,
-	chChunksIn <-chan Chunk,
-	chChunksOut chan<- Chunk,
-	chJobErrorsOut chan<- JobError,
+	columns []models.ColumnType,
+	chChunksIn <-chan models.Chunk,
+	chChunksOut chan<- models.Chunk,
+	chJobErrorsOut chan<- custom_errors.JobError,
 	wgActiveChunks *sync.WaitGroup,
 ) {
 	transformationPlan := computeTransformationPlan(columns)
@@ -59,7 +61,7 @@ func transformRowsMssql(
 				}
 
 				select {
-				case chJobErrorsOut <- JobError{ShouldCancelJob: true, Msg: "Transformation failed", Prev: err}:
+				case chJobErrorsOut <- custom_errors.JobError{ShouldCancelJob: true, Msg: "Transformation failed", Prev: err}:
 				case <-ctx.Done():
 				}
 				return
@@ -78,7 +80,7 @@ func transformRowsMssql(
 	}
 }
 
-func computeTransformationPlan(columns []ColumnType) []columnTransformPlan {
+func computeTransformationPlan(columns []models.ColumnType) []columnTransformPlan {
 	var plan []columnTransformPlan
 
 	for i, col := range columns {
@@ -123,7 +125,7 @@ func computeTransformationPlan(columns []ColumnType) []columnTransformPlan {
 
 const processChunkCtxCheck = 4096
 
-func processChunk(ctx context.Context, chunk *Chunk, transformationPlan []columnTransformPlan) error {
+func processChunk(ctx context.Context, chunk *models.Chunk, transformationPlan []columnTransformPlan) error {
 	for i, rowValues := range chunk.Data {
 		if i%processChunkCtxCheck == 0 {
 			if err := ctx.Err(); err != nil {
diff --git a/internal/app/models/colum-type.go b/internal/app/models/colum-type.go
index b0b7bbd..81e6a62 100644
--- a/internal/app/models/colum-type.go
+++ b/internal/app/models/colum-type.go
@@ -42,3 +42,29 @@ func (c *ColumnType) Nullable() bool {
 func (c *ColumnType) Type() string {
 	return c.unifiedType
 }
+
+func NewColumnType(
+	name string,
+	hasMaxLength bool,
+	hasPrecisionScale bool,
+	userType string,
+	systemType string,
+	unifiedType string,
+	nullable bool,
+	maxLength int64,
+	precision int64,
+	scale int64,
+) ColumnType {
+	return ColumnType{
+		name,
+		hasMaxLength,
+		hasPrecisionScale,
+		userType,
+		systemType,
+		unifiedType,
+		nullable,
+		maxLength,
+		precision,
+		scale,
+	}
+}