feat: implement extractor error handling and batch processing for MSSQL and Postgres

internal/app/models/colum-type.go

@@ -0,0 +1,44 @@
+package models
+
+type ColumnType struct {
+	name string
+
+	hasMaxLength      bool
+	hasPrecisionScale bool
+
+	userType    string
+	systemType  string
+	unifiedType string
+	nullable    bool
+	maxLength   int64
+	precision   int64
+	scale       int64
+}
+
+func (c *ColumnType) Name() string {
+	return c.name
+}
+
+func (c *ColumnType) UserType() string {
+	return c.userType
+}
+
+func (c *ColumnType) SystemType() string {
+	return c.systemType
+}
+
+func (c *ColumnType) Length() (length int64, ok bool) {
+	return c.maxLength, c.hasMaxLength
+}
+
+func (c *ColumnType) DecimalSize() (precision, scale int64, ok bool) {
+	return c.precision, c.scale, c.hasPrecisionScale
+}
+
+func (c *ColumnType) Nullable() bool {
+	return c.nullable
+}
+
+func (c *ColumnType) Type() string {
+	return c.unifiedType
+}

internal/app/models/main.go

@@ -0,0 +1,22 @@
+package models
+
+import "github.com/google/uuid"
+
+type UnknownRowValues = []any
+
+type Chunk struct {
+	Id           uuid.UUID
+	BatchId      uuid.UUID
+	Data         []UnknownRowValues
+	RetryCounter int
+}
+
+type Batch struct {
+	Id                    uuid.UUID
+	ParentId              uuid.UUID
+	LowerLimit            int64
+	UpperLimit            int64
+	IsLowerLimitInclusive bool
+	ShouldUseRange        bool
+	RetryCounter          int
+}