├── .DS_Store
├── .gitattributes
├── README.md
├── memorySQL.uml
├── memorySQL.umlcd
├── memorySQLUML.png
└── src
├── MainDriver.java
└── com
└── memorysql
└── model
├── Column.java
├── Database.java
├── Row.java
├── SQL.java
├── Table.java
├── Type.java
├── constraint
├── Constraint.java
├── IntegerConstraint.java
├── IsRequiredConstraint.java
└── StringConstrain.java
└── operator
├── EqualsOperator.java
├── NotEqualsOperator.java
└── Operator.java
/.DS_Store:
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https://raw.githubusercontent.com/deepanshujain92/MemorySQL/3e2643fa62ab4befd59bfa0e6dbb041a32019e57/.DS_Store
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/.gitattributes:
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1 | # Auto detect text files and perform LF normalization
2 | * text=auto
3 |
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/README.md:
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1 | # MemorySQL
2 | Machine Coding | Object Oriented Design for SQL in Memory
3 | 
4 |
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/memorySQL.uml:
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1 |
2 |
3 |
4 |
5 |
6 | Query(String tableName, Object value, String columnname, String columnsToSelect, Operator op) {
42 | List results = new ArrayList();
43 | Set> data = db.getTable(tableName).getRows().entrySet();
44 | for (Map.Entry entry : data) {
45 | if (op.applyOp(entry.getValue().getValues().get(columnname), value))
46 | results.add(entry.getValue());
47 | }
48 | return results;
49 | }
50 |
51 | // INSERT INTO EMPLOYEE values("");
52 | public void insert(String insertQuery) {
53 | String[] splitedQuery = insertQuery.toLowerCase().split("\\s");
54 | String[] values = parseValues(splitedQuery[3]);
55 | Table table = db.getTable(splitedQuery[2]);
56 | if (table == null) {
57 | System.out.print("Table not found");
58 | return;
59 | }
60 | Set columns = table.getColumns().keySet();
61 |
62 | if (values.length != columns.size()) {
63 | System.out.print("Values length invalid");
64 | return;
65 | }
66 | LinkedHashMap record = new LinkedHashMap();
67 |
68 | var wrapper = new Object() {
69 | int ordinal = 0;
70 | };
71 | columns.forEach(col -> insert(table, record, col, values[wrapper.ordinal++]));
72 |
73 | table.insert(record);
74 | }
75 |
76 | private void insert(Table table, Map record, String col, String value) {
77 | if (table.getColumns().get(col).type == Type.INTEGER)
78 | record.put(col, Integer.valueOf(value));
79 | else
80 | record.put(col, value);
81 | }
82 |
83 | private String[] parseValues(String splitedQuery) {
84 | return splitedQuery.replaceAll("values", "").replaceAll("\"", "").replaceAll("\\)", "").replaceAll("\"", "")
85 | .replaceAll("\\(", "").replaceAll(";", "").split(",");
86 | }
87 |
88 | }
89 |
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/src/com/memorysql/model/Table.java:
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1 | package com.memorysql.model;
2 |
3 | import java.util.*;
4 |
5 | public class Table {
6 | private String tableName;
7 | private HashMap rows;
8 | private LinkedHashMap columns;
9 | private Integer autoId;
10 |
11 | Table(String tableName) {
12 | this.tableName = tableName;
13 | this.rows = new HashMap<>();
14 | this.columns = new LinkedHashMap<>();
15 | this.autoId = 0;
16 | }
17 |
18 | public Map getColumns() {
19 | return columns;
20 | }
21 |
22 | public String getTableName() {
23 | return tableName;
24 | }
25 |
26 | public HashMap getRows() {
27 | return rows;
28 | }
29 |
30 | public void setRows(HashMap rows) {
31 | this.rows = rows;
32 | }
33 |
34 | public Integer getAutoId() {
35 | synchronized (autoId) {
36 | return autoId++;
37 | }
38 | }
39 |
40 | public void setAutoId(Integer autoId) {
41 | this.autoId = autoId;
42 | }
43 |
44 | public boolean insert(LinkedHashMap values) {
45 | Integer id = this.getAutoId();
46 | Set colNames = columns.keySet();
47 | for(String columnName: colNames) {
48 | columns.get(columnName).validate(values.get(columnName));
49 | }
50 |
51 | Row row = new Row(id, values);
52 | rows.put(id, row);
53 |
54 | return true;
55 | }
56 |
57 | public void deleteRow(int rowId) {
58 | rows.remove(rowId);
59 | }
60 |
61 | public void printAllRecords() {
62 | System.out.print(rows);
63 | }
64 |
65 | public Column createColumn(String columnName, Type type) {
66 | if(columns.containsKey(columnName)) {
67 | System.out.print("Column Already Exist");
68 | return null;
69 | }
70 | Column column = new Column(columnName, type);
71 | columns.put(columnName, column);
72 | return column;
73 | }
74 |
75 | public void Query(String query) {
76 |
77 |
78 | }
79 |
80 | }
81 |
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/src/com/memorysql/model/Type.java:
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1 | package com.memorysql.model;
2 |
3 | public enum Type {
4 | INTEGER, STRING
5 | }
6 |
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/src/com/memorysql/model/constraint/Constraint.java:
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1 | package com.memorysql.model.constraint;
2 |
3 | public interface Constraint {
4 | boolean validate(Object object);
5 | }
6 |
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/src/com/memorysql/model/constraint/IntegerConstraint.java:
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1 | package com.memorysql.model.constraint;
2 |
3 | public class IntegerConstraint implements Constraint{
4 | @Override
5 | public boolean validate(Object object) {
6 | return object.getClass().equals(Integer.class) && (int)(object) <=1024 && (int)(object) >=-1024;
7 | }
8 | }
9 |
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/src/com/memorysql/model/constraint/IsRequiredConstraint.java:
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1 | package com.memorysql.model.constraint;
2 |
3 | public class IsRequiredConstraint implements Constraint{
4 |
5 | @Override
6 | public boolean validate(Object object) {
7 | if(object == null || object == "")
8 | return false;
9 | return true;
10 | }
11 |
12 | }
13 |
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/src/com/memorysql/model/constraint/StringConstrain.java:
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1 | package com.memorysql.model.constraint;
2 |
3 | public class StringConstrain implements Constraint {
4 |
5 | @Override
6 | public boolean validate(Object object) {
7 | return object.getClass().equals(String.class) && object.toString().length() <=20;
8 | }
9 |
10 | }
11 |
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/src/com/memorysql/model/operator/EqualsOperator.java:
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1 | package com.memorysql.model.operator;
2 |
3 | public class EqualsOperator extends Operator {
4 |
5 | public EqualsOperator() {
6 | this.name = "equals";
7 | this.sign = "=";
8 | }
9 |
10 | @Override
11 | public boolean applyOp(Object filterValue, Object value) {
12 | return (filterValue.equals(value)|| filterValue == value);
13 | }
14 |
15 | }
16 |
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/src/com/memorysql/model/operator/NotEqualsOperator.java:
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1 | package com.memorysql.model.operator;
2 |
3 | public class NotEqualsOperator extends Operator {
4 |
5 | public NotEqualsOperator() {
6 | this.name = "not equals";
7 | this.sign = "!=";
8 | }
9 |
10 | @Override
11 | public boolean applyOp(Object filterValue, Object value) {
12 | return !(filterValue.equals(value)|| filterValue == value);
13 | }
14 |
15 | }
16 |
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/src/com/memorysql/model/operator/Operator.java:
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1 | package com.memorysql.model.operator;
2 |
3 |
4 | public abstract class Operator {
5 | String name;
6 | String sign;
7 |
8 | public abstract boolean applyOp(Object filterValue, Object value);
9 | }
10 |
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