Support check constraint backend (GoogleCloudPlatform#962)

* Check constraint backend (#9)

Backend Support for Check Constraint

* update api

* fix PR comment

* remove api call to while validating constraints

* Fixed db collation regex to remove collation name from the results

* renamed function name to formatCheckConstraints and added check if constraint name is empty

* fixed PR comments

* added test case for the empty check constraint name

* fix: added regular exprression to match the exact column

* fix: added regular expression to replace table name

* Added test case for the column rename for check constraint

* 1. Refactored GetConstraint function
2. Fixed inforschema unit tests

* added comment at handling case for check constraints

* reverted white spaces

* reverted white spaces

* nit: doesCheckConstraintNameExist

* added comments for doesCheckConstraintNameExist

* PR and UT fixes

* fix UT

* UT fix

* Removed isCheckConstraintsTablePresent function

* moved regex globally

* Fix UT

* fixed UT

* fixed handling of the constraints

* removed unused function

* added unit tests for incompatable name

* Combined unit tests

* added test case for the renaming column having substring of other column

* added the query changes which return distinct value

---------

Co-authored-by: taherkl <[email protected]>
Co-authored-by: Akash Thawait <[email protected]>
Co-authored-by: Vivek Yadav <[email protected]>

webv2/api/schema.go

@@ -523,57 +523,6 @@ func UpdateCheckConstraint(w http.ResponseWriter, r *http.Request) {
 	json.NewEncoder(w).Encode(convm)
 }
 
-func doesNameExist(spcks []ddl.CheckConstraint, targetName string) bool {
-	for _, spck := range spcks {
-		if strings.Contains(spck.Expr, targetName) {
-			return true
-		}
-	}
-	return false
-}
-
-// ValidateCheckConstraint verifies if the type of a database column has been altered and add an error if a change is detected.
-func ValidateCheckConstraint(w http.ResponseWriter, r *http.Request) {
-	sessionState := session.GetSessionState()
-	if sessionState.Conv == nil || sessionState.Driver == "" {
-		http.Error(w, fmt.Sprintf("Schema is not converted or Driver is not configured properly. Please retry converting the database to Spanner."), http.StatusNotFound)
-		return
-	}
-	sessionState.Conv.ConvLock.Lock()
-	defer sessionState.Conv.ConvLock.Unlock()
-
-	sp := sessionState.Conv.SpSchema
-	srcschema := sessionState.Conv.SrcSchema
-	flag := true
-	var schemaIssue []internal.SchemaIssue
-
-	for _, src := range srcschema {
-		for _, col := range sp[src.Id].ColDefs {
-			if len(sp[src.Id].CheckConstraints) > 0 {
-				spType := col.T.Name
-				srcType := srcschema[src.Id].ColDefs[col.Id].Type
-				actualType := mysqlDefaultTypeMap[srcType.Name]
-				if actualType.Name != spType {
-					columnName := sp[src.Id].ColDefs[col.Id].Name
-					spcks := sp[src.Id].CheckConstraints
-					if doesNameExist(spcks, columnName) {
-						flag = false
-						schemaIssue = sessionState.Conv.SchemaIssues[src.Id].ColumnLevelIssues[col.Id]
-						if !utilities.IsSchemaIssuePresent(schemaIssue, internal.TypeMismatch) {
-							schemaIssue = append(schemaIssue, internal.TypeMismatch)
-						}
-						sessionState.Conv.SchemaIssues[src.Id].ColumnLevelIssues[col.Id] = schemaIssue
-						break
-					}
-				}
-			}
-		}
-	}
-
-	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(flag)
-}
-
 // renameForeignKeys checks the new names for spanner name validity, ensures the new names are already not used by existing tables
 // secondary indexes or foreign key constraints. If above checks passed then foreignKey renaming reflected in the schema else appropriate
 // error thrown.