SqllrSnapshot (General SQL Parser Java Library Core 4.2.19 API)

Object
- gudusoft.gsqlparser.dlineage.dataflow.model.SqllrSnapshot

```
public final class SqllrSnapshot
extends Object
```
An immutable value projection of what one dlineage analysis observed and built, for the SQL-LR producer (plan docs/designs/data-lineage/09-sqllr-v2-runtime-driven-coverage-plan-zh.md, Section 3.1).
The snapshot holds values only: strings, numbers, flags and handles. It never holds a runtime model object, a parse tree node, a token, a parser, a resolver namespace, a catalog, a Throwable or anything that reads a ThreadLocal, so it stays readable after the analyzer is disposed and from any thread. Records refer to each other by handle: every object of the analysis (statement, name reference, model node, relationship, parse text) gets one handle, the first time the recorder sees it, and keeps it. Handle 0 means none.

Two kinds of values are kept apart. Events (SqllrSnapshot.ElementEvent, SqllrSnapshot.ReferenceEvent, SqllrSnapshot.Name, SqllrSnapshot.Statement) are copied when they happen, before the analysis de-duplicates or rewrites anything: a + a is two element events. The topology (SqllrSnapshot.Node, SqllrSnapshot.Relation, SqllrSnapshot.Contribution) is copied once, when the analysis is complete and before output materialization changes the model: a + a is one contribution, which lists both of its events.

Internal API of the SQL-LR producer.

Since:

4.2.17

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`SqllrSnapshot.Alternative` One alternative the resolver gave a name: where its column comes from, unflattened.
`static class`	`SqllrSnapshot.Anchor` Where a parse tree node lies: its class and its first and last tokens.
`static class`	`SqllrSnapshot.Call` A function or CASE the analysis built a result set for, described by its parse.
`static class`	`SqllrSnapshot.ColumnReference` A column reference of the parse, whether the analysis read it or not (a failed read leaves no event): its name and its resolution at the freeze.
`static class`	`SqllrSnapshot.Contribution` One element of a frozen relationship (its target, or one de-duplicated source) with the events that gave it.
`static class`	`SqllrSnapshot.Decision` A binding the analysis decided by a fallback (plan 06, Section 3.3, decision points), recorded before it acts on it: the reference as it stood, what was selected and why.
`static class`	`SqllrSnapshot.Declaration` A declared parameter or variable, used or not.
`static class`	`SqllrSnapshot.Derived` A statement of dynamic SQL text, with the statement whose analysis parsed it.
`static class`	`SqllrSnapshot.Element` A relationship element: the node it stands for and how the relationship reads it.
`static class`	`SqllrSnapshot.ElementEvent` An element added as a source of a relationship, or set as its target, copied when it happened.
`static class`	`SqllrSnapshot.Layout` The output layout of one query block: its items, also when there are none.
`static class`	`SqllrSnapshot.Name` A name reference the analysis read, copied when first seen.
`static class`	`SqllrSnapshot.Node` A node of the runtime model: a table, view, variable, result set, function, column, relation-rows pseudo column, process or routine, as it stood at the freeze.
`static class`	`SqllrSnapshot.Position` A `Pair3<Long, Long, String>` position of the model.
`static class`	`SqllrSnapshot.ReferenceEvent` A name reference the analysis read for a target, whether or not it added a source.
`static class`	`SqllrSnapshot.RegistryEntry` The members of one model registry, in the registry's order (processes, packages, routines, tables, ...).
`static class`	`SqllrSnapshot.Relation` A relationship as it stood at the freeze.
`static class`	`SqllrSnapshot.Resolution` A name's resolution as it stood at one moment: status, every alternative and the table linked to it.
`static class`	`SqllrSnapshot.Statement` A statement the analysis worked in, copied when first seen.
`static class`	`SqllrSnapshot.StructField` A column built for a field of a STRUCT that a select item constructs.
`static class`	`SqllrSnapshot.SyntaxError` A syntax error of a parsed unit.
`static class`	`SqllrSnapshot.Text` One parse text (a token list): an input unit's, or one the analysis parsed from dynamic SQL.
`static class`	`SqllrSnapshot.Token` A source token as the parse left it when it was copied.
`static class`	`SqllrSnapshot.TransformValue` A transform the analysis attached to a relationship element.
`static class`	`SqllrSnapshot.Unit` One parsed input unit.
`static class`	`SqllrSnapshot.WriteRow` One row an INSERT writes from a VALUES list (or DEFAULT VALUES), item by item.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`String`	`canonical()` The snapshot written canonically: equal snapshots, and only equal ones, write the same text.
`String`	`digest()` The SHA-256 of `canonical()`, in lower-case hex.
`List<SqllrSnapshot.ColumnReference>`	`getColumnReferences()` Every column reference of the analysed statements' parse, read or not, in text order.
`List<SqllrSnapshot.Decision>`	`getDecisions()` Every fallback decision, in recording order.
`List<SqllrSnapshot.Declaration>`	`getDeclarations()` Every declared parameter and variable of the analysed statements, used or not, in text order.
`List<SqllrSnapshot.Derived>`	`getDerived()`
`List<SqllrSnapshot.ElementEvent>`	`getElementEvents()` Every element event, in recording order.
`List<SqllrSnapshot.Layout>`	`getLayouts()` The output layout of every query block of the analysed statements, in text order.
`List<SqllrSnapshot.Name>`	`getNames()` Every name reference an event carries, in handle order.
`List<SqllrSnapshot.Node>`	`getNodes()` Every model node: those the model registers for output (processes, routines, tables, views, result sets), then any other node an element or member reaches, in handle order.
`String`	`getProjectionFailure()` Why copying the declarations, layouts, written rows and column references from the parse stopped (they are then incomplete), or null.
`List<SqllrSnapshot.ReferenceEvent>`	`getReferenceEvents()` Every reference event, in recording order.
`List<SqllrSnapshot.RegistryEntry>`	`getRegistry()` The model's registries, each in its own order; a node may also be reached only through a relationship.
`List<SqllrSnapshot.Relation>`	`getRelations()` Every relationship at the freeze, in creation order.
`List<SqllrSnapshot.Statement>`	`getStatements()` Every statement the analysis worked in, in handle order.
`List<SqllrSnapshot.StructField>`	`getStructFields()`
`List<SqllrSnapshot.Text>`	`getTexts()` Every parse text a copied token belongs to, by handle.
`List<SqllrSnapshot.Unit>`	`getUnits()` The parsed units, in analysis order.
`List<SqllrSnapshot.WriteRow>`	`getWriteRows()` Every row an INSERT of the analysed statements writes from VALUES (or DEFAULT VALUES), in text order.

Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - getTexts
```
public List<SqllrSnapshot.Text> getTexts()
```
    Every parse text a copied token belongs to, by handle.
  - getUnits
```
public List<SqllrSnapshot.Unit> getUnits()
```
    The parsed units, in analysis order.
  - getStatements
```
public List<SqllrSnapshot.Statement> getStatements()
```
    Every statement the analysis worked in, in handle order.
  - getNames
```
public List<SqllrSnapshot.Name> getNames()
```
    Every name reference an event carries, in handle order.
  - getNodes
```
public List<SqllrSnapshot.Node> getNodes()
```
    Every model node: those the model registers for output (processes, routines, tables, views, result sets), then any other node an element or member reaches, in handle order.
  - getRelations
```
public List<SqllrSnapshot.Relation> getRelations()
```
    Every relationship at the freeze, in creation order.
  - getElementEvents
```
public List<SqllrSnapshot.ElementEvent> getElementEvents()
```
    Every element event, in recording order.
  - getReferenceEvents
```
public List<SqllrSnapshot.ReferenceEvent> getReferenceEvents()
```
    Every reference event, in recording order.
  - getDerived
```
public List<SqllrSnapshot.Derived> getDerived()
```
  - getStructFields
```
public List<SqllrSnapshot.StructField> getStructFields()
```
  - getDecisions
```
public List<SqllrSnapshot.Decision> getDecisions()
```
    Every fallback decision, in recording order.
  - getRegistry
```
public List<SqllrSnapshot.RegistryEntry> getRegistry()
```
    The model's registries, each in its own order; a node may also be reached only through a relationship.
  - getDeclarations
```
public List<SqllrSnapshot.Declaration> getDeclarations()
```
    Every declared parameter and variable of the analysed statements, used or not, in text order.
  - getLayouts
```
public List<SqllrSnapshot.Layout> getLayouts()
```
    The output layout of every query block of the analysed statements, in text order.
  - getWriteRows
```
public List<SqllrSnapshot.WriteRow> getWriteRows()
```
    Every row an INSERT of the analysed statements writes from VALUES (or DEFAULT VALUES), in text order.
  - getColumnReferences
```
public List<SqllrSnapshot.ColumnReference> getColumnReferences()
```
    Every column reference of the analysed statements' parse, read or not, in text order.
  - getProjectionFailure
```
public String getProjectionFailure()
```
    Why copying the declarations, layouts, written rows and column references from the parse stopped (they are then incomplete), or null.
  - canonical
```
public String canonical()
```
    The snapshot written canonically: equal snapshots, and only equal ones, write the same text.
  - digest
```
public String digest()
```
    The SHA-256 of canonical(), in lower-case hex.

Class SqllrSnapshot

Nested Class Summary

Method Summary

Methods inherited from class Object

Method Detail

getTexts

getUnits

getStatements

getNames

getNodes

getRelations

getElementEvents

getReferenceEvents

getDerived

getStructFields

getDecisions

getRegistry

getDeclarations

getLayouts

getWriteRows

getColumnReferences

getProjectionFailure

canonical

digest